1.
Given that 6log(x + 4) = log64, find the value of x.
4
2
-2
-4
Answer: C
logbc = clogb
64 = 2 x 2 x 2 x 2 x 2 x 2 = 26
6log(x + 4) = log64
6log(x + 4) = log26
6log(x + 4) = 6log2
Compare the left side and the right side.
x + 4 = 2
x = 2 - 4
x = -2
2.
Find the number of even integers between 11 and 97.
43
44
45
53
Answer: A
Even numbers are number divisible by 2 without a remainder.
Set of even integers between 11 and 97 = {12,14,16,18,20,22,24,26,28,30,32,34,36,38,40,42,44,46,48,50,52,54,56,58,60,62,64,66,68,70,72,74,76,78,80,82,84,86,88,80,92,94,96}
The total number of elements in the set = 43
Alternate Solution
Find the interval between 97 and 11 and divide by 2
97 - 11 = 86
Even integers between 11 and 97 = = 43
3.
Find the 11th term of , ,1, 1, ... .
8
6
4
2
Answer: C
The sequence is linear.
Common difference = - = 1 - = 1 - 1 =
Un = a + (n - 1)d
Where n = nth term,
a = first term
d = common difference
a =
d =
U11 = + (11 - 1) x
U11 = + 10 x
U11 = + 5 x
U11 = +
U11 =
U11 =
U11 = 4
4.
1.639 X 10-2
1.639 X 10-1
1.639 X 101
1.639 X 102
Answer: C
5.
Make b the subject of the relation:
Ib = 1⁄2 (a+b)hAnswer: A
Ib = 1⁄2 (a+b)h
multiply through by 2
2 x Ib = 1⁄2(a + b)h
2b = 1(a + b)h
2b =(a + b)h
2b =ah + bh
Group like terms
factorize b out
Gives b(2 - h) = ah
Divide through by 2 - b to make b the subject
b(2 - h)⁄2-h = ah⁄2-h
b = ah⁄2-h
6.
Bala sold an article for N6,900.00 and made a profit of 15%. calculate his percentage profit if he had sold it for N6,600.00.
Answer: C
selling price = N6,900.00
Profit percent = 15%
percentage profit if he had sold if for N6,600.00
let C.P represent cost price
S.P represnt selling Price
% represent Profit percent
C.P = S.P - P
but put P = %P X C.P
put P = 15% x C.P
P = 0.15 C.P
Gives = C.P = S.P - ( 0.15 - C.P )
but S.P = 6,900.00
C.P = 6,900 - (0.15 C.P )
Group like terms
C.P + 0.15 C.P = 6,900.00
1.5 C.P⁄1.5 = 6,900.00⁄1.5
therefore cost price of the article is 6,000
If the owner of the article had sold it N6,600.000
Profit = Selling price - Cost Price
= 6,600 - 6000
N600.00
since profit is know
percent profit = P⁄C.P x 100
= 600⁄6000 x 100
10%
7.
Given that p = x - and q = x2 + , express q in terms of p.
q = (p2 + 2)
q = (p - 2)2
q = (p + 2)2
q = (p2 - 2)
Answer: A
p = x -
Every number is divisible by 1
x =
p = -
p =
p =
Square both sides of the equation.
p2 = ()2
(x2 - 1)2 = (x2 - 1) x (x2 - 1)
(x2 - 1)2 = x2(x2 - 1) - 1(x2 - 1)
(x2 - 1)2 = x2 x x2 - 1 x x2 - 1 xx2 - 1 x -1
(x2 - 1)2 = x4 - x2 - x2 + 1
(x2 - 1)2 = x4 - 2x2 + 1
p2 =
Divide each of the expressions at the right by the denominator (x2).
p2 = - +
p2 = x2 - 2 +
p2 = x2 + - 2
But q = x2 +
p2 = q - 2
p2 + 2 = q
8.
The total surface area of a solid cylinder is 165cm2.
If the base diameter is 7cm, calculate its height [Take ϖ = 22⁄7]Answer: B
diameter = 7cm
Area of cylinder = 165cm2 ϖ = 22⁄7
since radius = 35
165 = 8(22⁄7)(3.5)(h) + 2(22⁄7)(3.5)2
165 = 22h + 44⁄7 (12.25)
165 =22h + 77
f=group like terms
165 - 77 = 22h
88 =22h
divide through by 22
h=4
9.
If log102 = 0.3010 and log102y = 1.8060, find, correct to the nearest whole number, the value of y.
7
6
5
4
Answer: B
Applying logabc = c x logab = clogab
log102y = y x log102
But log102y = 1.8060
⇒ y x log102 = 1.8060
But log102 = 0.3010
Hence y x 0.3010 = 1.8060
Dividing both sides by 0.3010
⇒ y = 1.8060/0.3010 = 6
10.
Answer: B
11.
If the sequence x,4,16,y is Geometric Progression (GP), find the ratio of x:y.
64:1
8:1
1:3
1:64
Answer: D
Geometric sequence is a sequence of numbers where each term after the first is found by multiplying the previous one by a fixed, none-one number called the common ratio
Rules
For the sequence a1, a2, a3, a4 ...
Where a1 = first term
Where a2 = second term
Where a3 = third term
Where a4 = forth term
r = a2 / a1 = a3 / a2 = a4 / a3
Where r = common ratio
Thus the common ratio (r) is the same for all calculations
Hence 4/x = 16/4
4/x = 4
Multiplying both sides by x
x x 4/ x = 4 x x
4x = 4
Dividing both sides by 4
x = 1
16/4 = y/16
4 = y/16
Multiplying both sides by 16
16 x 4 = y/16 x 16
y = 64
⇒ x:y = 1:64
12.
In the diagram, MN // PQ. Find the value of (x + y).
90°
60°
40°
30°
Answer: C
The angle adjacent to 110° is (180 - 110)° (Angles on a straight line sum up to 180°)
(x + 4y)° = The angle adjacent to 110° (Alternate angles are the same)
(x + 4y)° = (180 - 110)°
x + 4y = 70 ------ (equation 1)
(x + 4y)° = (2x + y)°(Vertically opposite angles are the same).
Since x + 4y = 70, 2x + y is also 70
2x + y = 70 ------ (equation 2)
Solve equation 1 and 2 simultaneously.
Get rid of x by multiplying equation 1 by 2 and subtracting equation 2 from equation 3.
x x 2 + 4y x 2 = 70 x 2
2x + 8y = 140 ------ (equation 3)
Equation 3 - Equation 2
7y = 70
Divide both sides by 7
y =
y = 10
Subtitute y = 10 into equation 1
x + 4 x 10 = 70
x + 40 = 70
x = 70 - 40
x = 30
x + y = 30 + 10
x + y = 40
13.
Factorize: p2q2 - 6pqr + 9r2
(pq-3r)2
(pq - 3r)(pq + 3r)
(pq+3r)2
(pr+3q)(pr-3q)
Answer: A
Since 3 can go into 6 and 9, split -6pqr into -3pqr and -3pqr
⇒ p2q2 - 6pqr + 9r2 = p2q2 -3pqr -3pqr + 9r2
Now factorize
p2q2 -3pqr -3pqr + 9r2
pq(pq - 3r) -3r(pq-3r)
(pq-3r)(qp-3r)
since pq-3r = pq-3r, the multiplication makes it square
(pq-3r)2
The equation above is similar to the general factorization rule of (a-b)2
(a-b)2 = a2 - 2ab + b2
Thus the first term square then the sign (either + or -) and 2 times the first and second terms + the second term square
Similarly (a+b)2 = a2 +2ab + b2
The first term for the above equation is pq and the second term is 3r and the sign is -
You can apply the (a-b)2 = a2-2ab+b2 to expand the (pq-3r)2, you will realize you will get the expression you were asked to factorize
14.
Which of the following describes the set P = {1,2,3,4,5,6}?
P = {Prime numbers < 7}
P = {x:x is a positive integer < 7}
P = {rational numbers < 7}
P = {x:x is a real number < 7}
Answer: B
Prime number: A number that is divisible only by itself and 1
NB: 1 is not a prime number hence the option is not A
Integer: A whole number (not a fraction) that can be positive, negative or zero. e.g ...,-5,-4,-3,-2,-1,0,1,2,3...
P is a set of positive (No negative) integers and less than 7, hence the correct answer is B
Rational Number: A number such as 5/8 that can be expressed as quotient or fraction p/q of two integers.
Real Number: Any positive or negative number. This includes all integers and all rational and irrational numbers.
15.
find the equation of a straight line passing through the point (1,-5) and having gradient of 3⁄4
3x-4y-23 = 0
3x-4y+23 =0
3x+4+23 =0
3x+4y-23= 0
Answer: A
Equation of a line y = mx + c
If point (1,-5) is given and gradient 3⁄4
y = -5
x = 1
y = mx + c
Gives : -5 = 3⁄4 (1) + c
-5 = 3⁄4 + c
Group like terms
-5-3⁄4 = c
-5⁄1 -3⁄4 = c
-20-3⁄4 = c
-23⁄4
y = 3⁄4x - 23⁄4
multipy through by 4
4 x y = 4 X 3⁄4x - 23⁄4 x 4
4y =3x - 23
0 =3x - 23 - 4y = 0
3x - 4y - 23 = 0
16.
3p = 4q and 9p = 8q - 12, find the value of pq
Answer: D
3p = 4q ...... 1eqn
9p = 8p - 12 .......2eqn
multiply equation 1 by 3
3 x 3p = 3 x 4q
9p = 12q ..... 3eqn
put 3eqn into 2eqn
12q = 8q - 12
12q - 8q = -12
4q⁄4 =-12⁄4
q = 3
put q = -3 into 1
3p = 4(-3)
3P⁄3 = -12⁄3
Pq = (-4)(-3)
12
17.
If A = b(a + b), make a the subject of the relation.
a = b -
a = - b
a = + b
a = - b
Answer: B
A = b(a + b)
Get rid of the fraction by multiplying both sides by 2
2 x A = 1 x b(a + b)
2A = b(a + b)
Divide both sides by b
= a + b
- b = a
18.
Answer: B
19.
Answer: B
Significant figure rules
* Non-zero digits are always significant (1,2,3,4,5,6,7,8,9)
* Any zeros between two significant digits are significant
* A final zero or trailing zeros in the decimal portion ONLY are significant e.g .500 or .63200 the zeros are significant
.006 or .000968 the zeros are NOT significant
Applying the above rules to 9453 x -6
Change it to fraction
Since the exponent is negative, you have to move to the left 6 times and place the decimal point there with leading zeros before the digits 9453
9453 x -6 = 0.009453
The significant figures are 9,4,5 and 3. Since it is 3 significant figures, it ends on 5
Thus 0.00945 is the answer
NB: The leading zeros before 9453 are not significant as explained by the above rule. Hence they were not counted as part of the significant digits.
20.
Answer: C
let represent initial term d represent difference
a = 6
d = common diffence
To find common diffence is the second term minus the first time that's current minus intial term
d = p - 6 = 14 -p
p - 6 = 14 - p
Group like terms
p + p = 14 + 6
2p⁄2 = 20⁄2
p = 10
21.
In the diagram,POS and ROT are straight lines.QPQP is a parallelogram,
|QS| = |QT| and ∆OST = 50°; Calculate tyhe value of ∆OPQ
Answer: D
∆OST = OTS (Isocicoles)
OTS = 50°
considering ∆OST
50 + 50 +∆SOT = 180 100 + ∆SOT =180 Group like terms ∆SOT = 180 ∆SOT = 80° ∆SOT = ∆ROP = 80° (vertical opposite angles are equal 80 + OPQ = 180 OPQ =180 - 80 OPQ = 100
22.
The length of a rectangular lawn is 3 cm longer than the width. If the perimeter is 42 cm, find the width.
6 cm
9 cm
12 cm
15 cm
Answer: B
Perimeter is the summation of all the dimension of the boundaries of a shape.
Let w = the width of the rectangular lawn.
Length is 3 cm longer than the width → Length = w + 3
Perimeter = 2(w + 3) + 2w
But perimeter of the rectangular lawn = 42
2(w + 3) + 2w = 42
2 x w + 2 x 3 + 2w = 42
2w + 6 + 2w = 42
4w = 42 - 6
4w = 36
Divide both sides by 4
w =
w = 9 cm
23.
Answer: C
C
NB: Change the mixed fractions to improper fractions
Explanation:
Multiply the whole number(A) by the denominator(c) and add the numerator(b) to the result(Axc). Divide everything by the denominator(c).
⇒ 21⁄2 = (2x2 + 1)⁄2 = 5⁄2
⇒ 11⁄2 = (1x2 + 1)⁄2 = 3⁄2
Concepts
a = a/1
b = b/1
Explanation:
Change the ÷ to x (multiplication). To do so:
Reciprocate the fraction at the right side of the ÷
Reciprocate means the top goes to the down and the down comes to the top
Explanation:
The numerators multiply each other over the denominators multiplying each other.
Thus the products of the numerators over the products of the denominators
Product means multiplication
Applying all the above concepts
24.
Answer: A
Answer is A
3 x 9 1 + x = 27-x
Concept
Ab x Ac = Ab+c
Thus if the bases are the same, we can add the indexes (superscripts)
3 can go into the other numbers(9,27) hence we change then to have base 3
9 = 31x 31 = 31 + 1=32
27 = 31x 31 x 31 =31+1+1 = 33
⇒ 3 x 32(1 + x) = 33(-x)
But 3 = 31, thus every number is raised to the power 1
⇒ 31 x 32(1 + x) = 33(-x)
Applying Ab x Ac = Ab + c
3 1 x 32(1+ x) = 31 + 2(1 + x )
31+2(1+ x) = 33(-x)
Concept
If Ab = Ac ⇒ b = c
Thus if the base at the left side of the equation, is the same as the right side of the equation, then the powers are the same
∴ 1 + 2(1 + x ) = 3(-x)
Concept
a(b + c ) = a x b + a x c
a(b - c ) = a x b - a x c
Thus the number outside the bracket multiplies each of the number in the bracket and the sign ( + or - ) is(are) maintained
-x = -1 x x
3(-x) = 3 x (-1) x x = -3x
1 + 2(1 + x ) = 1 + 2 x 1 + 2 x x
= 1 + 2 + 2x
= 3 + 2x
1 + 2(1+x) = 3(-x)
⇒ 3 + 2x = -3x
Grouping the x at the left and the rest at the right
Concept
If the sign is positive(+) and crosses to the other side of the equation the sign changes to negative ( - ) and the vice versa
2x + 3x = -3
5x = -3
Concept
Divide both sides by the number multiplying the number or variable (x)
5x⁄5 = -3⁄5
x = -3⁄5
25.
Not drawn to scale
In ∆XYZ, ∣YZ∣ = 32 cm, ∠YXZ = 52 ° and ∠XZY = 90 °.
Find, the correct to nearest centimetre. ∣XZ∣.
Answer: C
∅ = 52
opposite ∣YZ∣ = 32
Adjacement ∣XZ∣ = ?
since opposite is known and we are ask to find adjacent (∣XZ∣)
tan∅ formular will be appiead.
which says tan∅ = opposite⁄Adjacement ∣YZ∣⁄∣XZ∣
tan(32) = 32⁄∣XZ∣
cross multiply
tan32⁄1 = 32⁄∣XZ∣
∣XZ⁄ tan(52) =32
On your scientific calculator tan(52) = 0.52
∣XZ (∅.28) = 32
making ∣XZ∣ the subject divide through by 0.53
∣XZ⁄0.53 = 32⁄1.28
∣XZ = 32⁄1.28
∣XZ∣ = 25cm
26.
Dina and Rose were given GH₵ 875.08 to be shared in the ratio 3:2 respectively. If Rose shared her part of the money between Efua and Ama in the ratio 1:2 respectively, how much was Ama's share?
GH₵ 116.68
GH₵ 175.02
GH₵ 233.35
GH₵ 340.32
Answer: C
The sum of the ratio represents the entire money shared.
Sum of ratios = 3 + 2
Sum of ratios = 5
Rose's ratio is 2.
If 5 = GH₵ 875.08
2 = = GH₵ 350.032
Rose's share = GH₵ 350.032
Sum of Efua's and Ama's ratios = 1 + 2
Sum of Efua's and Ama's ratios = 3
Ama's ratio = 2
The sum of ratios represents the entire money both shared.
If 3 = GH₵ 350.032
2 = = GH₵ 233.3546666666667
Ama's share = GH₵ 233.35
27.
Given that 4x + 6y = 5 and 2x + 4y = 3, find the value of (x + 2y)
-1
-1
1
1
Answer: D
Method I
4x + 6y = 5 --- eqn (1)
2x + 4y = 3 --- eqn (2)
Multiply equation 2 by 2 to eliminate x
2x x 2 + 4y x 2 = 3 x 2
4x + 8y = 6 --- eqn (3)
Equation 3 - Equation 1
2y = 1
Divide both sides by 2
y =
Subtitute y = in equation 1
4x + 6 x = 5
4x + 3 = 5
4x = 5 - 3
4x = 2
Divide both sides by 4
x =
x =
x + 2y = + 2 x
x + 2y =
x + 2y =
x + 2y = 1
Method II
Express 2x + 4y = 3 to be in the form (x + 2y) and make (x + 2y) the subject
2x + 4y = 3
Factorize 2 out.
2(x + 2y) = 3
Divide both sides by 2 to make (x + 2y) the subject.
(x + 2y) =
Change the improper fraction to mixed fraction.
(x + 2y) = 1
28.
Find the truth set of (3 + x)(1 - x) > 9 - x2.
{x:x > 3}
{x:x > -3}
{x:x < 3}
{x:x < -3}
Answer: D
(3 + x)(1 - x) > 9 - x2
Expand the bracket
3(1 - x) + x(1 - x) > 9 - x2
3 - 3x + x - x2 > 9 - x2
3 - 2x - x2 > 9 - x2
- x2 cancels each other at both sides of the equation.
3 - 2x > 9
- 2x > 9 - 3
- 2x > 6
Divide both sides by - 2. When dividing by a negative, the sign changes direction.
x <
x < -3
29.
An arc subtends an angle of 72° at the center of the circle. Find the length if the radius of the circle is 3.5 cm [Take Π = 22⁄7]
Answer: B
length of an arc = ∅⁄360 X 2Πr
Angle (Π) = 72
Π = 22⁄7
length of arc = 72;⁄360 x 2 22;⁄7 x 3.5
= 4.4
30.
(27.63)2 - (12.37)2
Answer: A
diffence of two squards
(27.63 - 12.37)(27.63 + 12.37)
610.4
Run it to three dicimal place
since 4 is less than 5 you maintian it
31.
The graph of y = x2 + 4x - 6 is drawn and a linear graph is drawn on the axes such that the intersection of the two graphs gives the solution to the equation x2 + 4x - 7 = 0. Find the equation for the linear graph.
x = 1
x = -1
y = 1
y = 1
Answer: D
Substitute y = x2 + 4x - 6 into x2 + 4x - 7 = 0
-7 = -6 - 1
x2 + 4x - 7 = 0
x2 + 4x - 6 - 1 = 0
But x2 + 4x - 6 = y
y - 1 = 0
y = 0 + 1
y = 1
32.
The exterior angles of a quadrilateral are 61°,76°, (x + 10)° and (2x + 45)°.
Find the value of x.
45
60
66
56
Answer: D
Concept
Sum of exterior angles of any polygon = 360°
61° + 76° + (x + 10)° + (2x + 45)° = 360°
61 + 76 + x + 10 + 2x + 45 = 360
3x + 192 = 360
3x = 360 - 192
3x = 168
Divide both sides by 3
x =
x = 56
33.
If = , find x:y
5:3
4:1
3:5
1:4
Answer: B
=
Cross multiply. The numerator at the left side multiplies the denominator at the right then equal to then the numerator at the right also multiplies the denominator at the left.
3 x (x + y) = 5 x (x - y)
3x + 3y = 5x - 5y
3y + 5y = 5x - 3x
8y = 2x
Divide both sides by y
8 =
Divide both sides by 2
=
Division is :
8:2 = x:y
2 can divide itself once and 8, 4 times.
4:1 = x:y
34.
In the diagram P,Q,R,S are points on the circle. If ∠PQS = 32o and ∠PRQ = 61o, find ∠QPS.
32o
61o
87o
93o
Answer: C
Inscribed angles subtended by the same are equal.
∠PSQ = ∠PRQ = 61o
Sum of angles in are triangle is 180o
∠QPS + ∠PSQ + ∠PQS = 180o
∠QPS + 61 + 32 = 180
∠QPS + 93 = 180
∠QPS = 180 - 93
∠QPS = 87o
35.
If (0.25)y find the value of y.
Answer: A
(25⁄100)y = 32
(1⁄4)y 32
log(1⁄4)y = log32
ylog 0.25 = log32
y = log32⁄log0.25
y = -2.5
y = -25⁄10
y = -5⁄2
36.
Solve the equation: t - 9⁄5 = -11⁄15 .
t = 3⁄5
t = 11⁄15
t = 4⁄5
t = 13⁄15
Answer: B
Change the mixed fraction to an improper fraction.
Explanation:
Multiply the whole number(A) by the denominator(c) and add the numerator(b). Divide everything by the denominator(c).
⇒ 11⁄15 = (1x15+1)⁄15 = 16⁄15
⇒ t - 9⁄5 = -16⁄15
Get ride of the denominators by multiplying both sides by the least common multiple(LCM)
The denominators are 5 and 15,5 can go into 15, hence the LCM is 15
tx15 -15x9⁄5 = 15x-16⁄15
15t - 27 = -16
15t = -16+27
15t = 11
15t⁄15 = 11⁄15
t = 11⁄15
37.
The interior angle of a polygon are 3x°;2x°;4x°; 3x°; and 6x°. Find the size of the smallest angle of the polygon.
Answer: C
Since the angle of the polygon are five
It means the polygon is pentagon
interior angles of polygon = n-2x180⁄n
number of side (n) = 5
Interior angles of pentagon = (5-2)X180⁄5
=3X180⁄5
=540⁄5
108
since 180 is the interior
3x which is the smalllest angle
3x⁄3 = 108⁄3
x =60°
the smallest angle is 60°
38.
Answer: B
39.
There are 8 boys and 4 girls in a lift.what is the probability that the first person who steps out of the lift will be a boy
1⁄4
2⁄3
1⁄3
3⁄4
Answer: B
Number of Boys = 5
Number of Girls = 4
Total pupils = 8 + 4
To get the probability of boys out of lift is the number of boys over the total number of pupils
P(a boys steps out of the lift) = 8⁄12
2⁄3
40.
y varies inversely as the square of x. When x = 3, y = 100. Find the value of x when y = 25.
x = 30
x = 12
x = 6
x = 5
Answer: C
y ∝ 1⁄x2
NB: ∝ is the symbol for proportional
inversely proportional is 1 over the expression
directly proportional is just the expression (It would had been y ∝ x2)
a constant(=k) is introduced in place of the ∝
y = kx1⁄x2
y = k⁄x2
Use the known values to calculate the constant(k) to get the general expression
y = 100 and x = 3
⇒ 100 = k⁄32
100 = k⁄9
100x9 = k
⇒ k = 900
∴ y = 900⁄x2
when y = 25
⇒ 25 = 900⁄x2
25 x x2 = 900
x2 = 900⁄25
x2 = 36
√x2 = √36
x = 6
NB: The square root of a squared number or variable is equal to the number or variable
41.
The area of a trapezium is 49 cm2. If the parallel sides are 6 cm and 7 cm long, find, correct to one decimal place, the distance between the parallel sides.
6.5 cm
6.8 cm
7.4 cm
7.5 cm
Answer: D
Diagram Illustration
Area = 49 cm2
a = 6cm, b = 7cm
⇒ 49 cm2 = 1/2 x (6cm + 7 cm) x h
49cm2 = 1/2 x (13cm) x h
Multiply both sides by 2
2 x 49cm2 = 1 x (13cm) x h
Divide both sides by 13cm
98 cm2 / 13 cm = 1 x h
⇒ h = 98/13 = 7.53846 = 7.5 (One decimal place)
42.
36. The foot of a ladder is 6 m from the base of an electric pole the top of the ladder rests against the pole at a point 8 m above the ground. How long is the ladder
Answer: B
Let label the part A,B and C
to find the ladder we use pythagories theorem
which says ∣AB∣2+∣BC∣2 = ∣AC∣2
∣AB∣ =6m,
∣B∣=8m,
∣AB∣2+∣BC∣2 = ∣AC∣2
62+82 = ∣AC∣2
36 + 64 = ∣AC∣2
100 ∣AC∣2
Root both side
√100 = √∣AC∣2
√100 = AC
10 = AC
The ladder is 10 m long
43.
Simplify , where x ≠ 3
Answer: B
9 - x2 is a difference of two square.
a2 - b2 = (a+b)(a-b)
9 = 3 x 3 = 32
9 - x2 = 32 - x2
32 - x2 = (3+x)(3-x)
=
Factorize x out in the denominator.
=
(3-x) cancels each other
=
44.
If the area of the trapezium MNOP is 300 cm2, find the value of x.
15 cm
12 cm
10 cm
20 cm
Answer: A
The area of the trapezium is the summation of the area of the triangle and the rectangle.
Area of triangle = x base x height
Area of a rectangle = Length x Breadth
Base of the triangle = 24 - 16 = 8
Height of the triangle = x
Breadth of rectangle = x
300 = x 8 x x + 16 x x
2 divides itself once and 8, 4 times.
300 = 4x + 16x
300 = 20x
Divide both sides by 20
x = = 15
45.
Given that P ∝ and x ∝ vt express P in terms of v and t.
P ∝
P ∝
P ∝ vt
P ∝
Answer: B
P ∝
Replace x by vt
P ∝
v2 = v x v
P ∝
The v cancel each other.
P ∝
46.
2x2 -4x + 6 = 0
4x2 -4x - 3 = 0
2x2 +3x + 4 = 0
4x2 -4x + 3 = 0
Answer: B
Change the mixed fraction to improper fraction
Rule
If α and β are the two roots of a quadratic equation, then the formula to construct the quadratic equation is:
x2 - (α + β)x + αβ = 0
Thus, x2 - (sum of roots)x + product of roots = 0
⇒ x2 - (-1/2 + 3/2)x + (-1/2 x 3/2) = 0
-1/2 + 3/2 = (-1+3)/2 = 2/2 = 1
Rule
-1/2 x 3/2 = (-1x3)/(2x2) = -3/4
⇒ x2 - (1)x + (-3/4) = 0
x2 - x - 3/4 = 0
NB: + - = - ⇒ + - 3/4 = -3/4
Multiply both sides by 4
4x - 4x - 3 = 0
47.
Find the angle which arc of the length 22 cm subtends at the centre of a circle of radius 15cm. [Take π = 22⁄7 ]
Answer: C
Length of an arc = 22 cm
raduis =
π = 22⁄7
angle (∅)= ?
formular for length of an arc = ∅⁄360 x 2πr
since length of an arc =22 cm
r = 15 and π = 22⁄7
22 = π⁄360 X 2(22)⁄7 X 15
22 = π⁄360 X 44⁄7
22 = π⁄360 X 94.286
22 = 94.2860⁄360
22⁄0.262 = 0.2620⁄0.262
π =22⁄0.262
π = 84
The angle is 84 °
48.
42
45
54
64
Answer: C
Change the mixed fractions to improper fractions
Rule
Rules
Thus, reciprocate/switch the numerator and denominator at the right and change the division to multiplication
Thus, the numerators multiply each other and the denominators multiply each other
Multiply both sides by 96
96 x 9/16 = x
16 goes into 96, 6 times
6 x 9 = x
x = 54
49.
If y varies inversely as x and y = 6 when x = 3, find y when x = 9
4
3
2
1
Answer: C
y ∝ 1 / x
NB: Inversely = 1 / the relation
Varies directly = Relation 1 ∝ Relation 2
Find the constant of the relation
Let k = the constant
y = k x 1/x
When y = 6, x is 3
⇒ 6 = k/3
Multiplying both sides by 3
⇒ k = 6 x 3 = 18
Hence y = 18/x
When x = 9
⇒ y = 18 / 9 = 2
50.
Answer: D
Answer is D
Use a venn diagram to illustrate
In a class of 39 student ⇒ n(u)=39
let F represent students who offer Fante ⇒ n(F)= 25
Let T represent students who offer Twi ⇒ n(T)= 19
Five student do not offer any of the two languages ⇒ 5 are outside the sets F and T
Let n represent number of student who offer both languages
NB: You need to substract the number of the students who offer both languaes from each of the languages to get the students who offer only that languages.
When we add all the parts in the venn diagram we are to get the total number of students n(u) = 39
(25 - n )+ n + (19 - n) + 5 =39
25 - n + n + 19 -n + 5 = 39
-n + 49 = 39
-n = 39 - 49
-n = -10
-n⁄-1 = -10⁄ -1
n = 10
Only Twi = 19-n
⇒ Only Twi = 19 - 10 = 9
4b2– ab + (a + 9b)2 – a2.
4b2 – ab + (a + 9b)2 – a2
step 1: Expand (a + 9b)2 to give (a + 9b) (a + 9b)
4b2 – ab + (a + 9b) (a + 9b) – a2
step 2: Expand the bracket:
=4b2 – ab + a2 + 18ab + 81b2 – a2
step 3: Group like terms:
= 4b2 + 81b2 – ab + 18ab + a2 - a2
= 4b2 + 81b2 – ab + 18ab
= 85b2 + 17ab
step 4: Factorize 17b out:
= 17b(5b + a)
Since Z = 8, x = 4, y = 1/8, substitute them in place of the variables.
The first three terms of an Arithmetic Progression (A.P:) are (x + 1),(4x - 2) and (6x - 3)
respectively.If the last term is 18, find the:(a)
vale of x;
(b)
Sum of the terms of the progression.
Notes
Arithmetic Progression
Is a sequence of numbers such that the difference between the consecutive terms is constant.
E.g The sequence 1,3,5,7,9.. is an arithmetic progression with a common difference of 2
an = a1 + (n - 1)d
an = The value of the sequence number of on the nth position.
a1 = the first number in the sequence
d = the common difference
d = an + 1 - an (The difference between two consecutive sequence numbers)
d is the same for all consecutive numbers used for the calculator.
Thus an + 2 - an + 1 = an + 1 - an
For instance, the common difference for the sequence a1, a2, a3, a4, a5, a6 .... will be calculated as:
a2 - a1 = a3 - a2 = a5 - a4 = a6 - a5
NB: The common difference (d) is the higher sequence number value - lower previos sequence number.
For the sequence 1,3,5,7,9
⇒ d = 3 - 1 = 5 - 3 = 7 - 5 = 9 - 7 = 2
Summation of Arithmetic Progression
Sn = n/2 (a1 + an)
Sn = n/2 [2a1 + (n - 1)d]
If the last number is know the summation can also be writen as
Sn = n/2 [a1 + l]
where l = last term
(a)
A. P = (x + 1), (4x - 2) and (6x - 3)
⇒ From the knowledge of common difference calculation
(4x - 2) - (x + 1) = (6x - 3) - (4x - 2)
NB Common difference is the same for all consecutive terms
⇒ 4x - 2 - x - 1 = 6x - 3 - 4x - -2
4x - 2 - x - 1 = 6x - 3 - 4x + 2
3x - 3 = 2x - 1
3x - 2x = -1 + 3
x = 2
(b)
Since we are given the last term, we are to use the summation formula with the last term in it.
Sn = n⁄2 [a1 + l]
We need to calculate the (n) position for the last number (l)
an = a1 + (n - 1)d
x = 2
⇒ first term = x + 1 = 2 + 1 = 3
Second term = 4x - 2 = 4 x 2 - 2 = 6
Third term = 6 x 2 - 3 = 9
The sequence = 3,6,9...18
⇒ a1 = 3
d = 6 - 3 = 9 - 6 = 3
But an = a1+(n-1)d
an = 18
a1 = 3
d = 3
⇒ 18 = 3+(n-1)x3
18 = 3+3n-3
18 = 3n
3n⁄3 = 18⁄3
n = 6
⇒ Sn = n⁄2[a1+l]
Sn = 6⁄2[3+18]
Sn = 63
(a)
Solve, correct to one decimal place, tan (θ + 25o) = 5.145, where 0o ≤ θ ≤ 90o.
(b)
In the relation t = m √(n2 + 4r):
(i)
make n the subject of the relation;
(ii)
find the positive value of n when t = 25, m = 5 and r = 4.
(a)
tan (θ + 25) = 5.145, where 0o ≤ θ ≤ 90o
Take the tan-1 (tan inverse) of both sides
tan-1 (tan (θ + 25) = tan-1 (5.145)
NB: tan-1 clears the tan and leaves the angles for you to be able to solve (tan-1 x tan1 = tano = 1)
⇒ θ + 25o = 79.00o
θ = 79.00 - 25
θ = 54.00
θ = 54.0 (one decimal place)
NB: Tan-1 on most calculator is obtained by pressing SHIFT and tan key
To clear a cos take cos-1 of both sides and to clear a sin take sin-1 of both sides.
(b)
(i)
t = m√(n2+ 4r)
Remove the √ by sqauring both sides of the equation.
t2 = (m √(n2 + 4r))2
t2 = m2 (√n2 + 4r)2
t2 = m2 x (n2 + 4r)
NB (a X b)n = a1 x n x b1 x n
(ac x bd)n = ac x n x bd x n
m√(n2 + 4r) = m x √(n2 + 4r)
⇒ (m√(n2 + 4r))2 = m1x2 x (√(n2 + 4r))2
√a = a1⁄2
⇒ (√a)2 = (a1⁄2)2 = a1 = a
⇒ t2 = m2 x (n2 + 4r)
t2 = m2 x n2 + m2 x 4r
t2 = m2 x n2 + 4m2r
t2 - 4m2r = m2 x n2
(t2- 4m2r)⁄m2 =n2
Take √ of both sides to remove the sqaure on the n
⇒ √((t2- 4m2r)⁄m2) = √n2
n = √((t2- 4m2r)⁄m2)
(ii)
t = 25, m = 5 and r = 4
n = √((t2- 4m2r)⁄m2)
substituting the values
n = √(252 - 4 x 52 x 4⁄52)
n = √225/25
n = √9
n = 3
The angle of a sector of a circle with radius 22cm is 60o. If the sector is folded such that the straight edges coincide, forming a cone,calculate correct to one decimal place, the:
(a)
radius;
(b)
height;
(c)
volume;
From the above diagram, the length of the arc becomes the circumference of the base of the cone.
radius of the circle = 22cm
θ = 60o
(a)
⇒ The radius of the cone = 3.67cm
(b)
The height (h) can be calculated using pythagoras theorem
The c (hypotanus is always the side facing the right angle (⊾))
⇒ 222 = 3.672 + h2
222 - 3.672 = h2
470.53 = h2
Take the square root (√) of both sides to get ride of the square
√470.53 = h
21.69 = h
⇒ The height of the cone = 21.69cm
(c)
Volume = ⅓ x 22⁄7x3.672 x 21.69
Volume = 306.05cm3
NB: Unit of area = unit square (e.g cm2,m2) and unit of volume = unit cubic (e.g cm3, m3)
Cross multiple:
5(5y – x) = 1(8y + 3X)
Expand the bracket:
25Y – 5X = 8Y + 3X
Group like terms and add:
25Y- 8Y = 3X + 5X
17Y = 8X
Divide through by 8.
Divide through by Y to make X the numerator