Change the mixed fractions to improper fractions.

22$\frac{1}{2}$ = $\frac{\mathrm{22\; x\; 2\; +\; 1}}{2}$

22$\frac{1}{2}$ = $\frac{\mathrm{44\; +\; 1}}{2}$

22$\frac{1}{2}$ = $\frac{45}{2}$

7$\frac{1}{2}$ = $\frac{\mathrm{7\; x\; 2\; +\; 1}}{2}$

7$\frac{1}{2}$ = $\frac{\mathrm{14\; +\; 1}}{2}$

7$\frac{1}{2}$ = $\frac{15}{2}$

Total time spent to school = $\frac{45}{2}$ minutes + $\frac{15}{2}$ minutes

Total time spent to school = $\frac{\mathrm{45\; +\; 15}}{2}$ minutes

Total time spent to school = $\frac{60}{2}$ minutes

Total time spent to school = 30 minutes

Method I

The entire minutes spent to school is 100%.

If 30 minutes = 100%
$\frac{45}{2}$ minutes = $\frac{45}{2}$ x 100% ÷ 30

2 divides itself once and 100, 50 times.

$\frac{45}{2}$ minutes = $\frac{\mathrm{45\; x\; 50\%}}{30}$

$\frac{45}{2}$ minutes = 15 x 5%

Note: The zero in 50 and 30 cancel each other. 3 divides itself once and 45, 15 times.

$\frac{45}{2}$ minutes = 75%

Method II

Percentage = $\frac{\mathrm{Number}}{\mathrm{Total}}$ x 100%

Percentage (walking) = $\frac{45}{2}$ ÷ 30 x 100%

Every number is being divided by 1

30 = $\frac{30}{1}$

Percentage (walking) = $\frac{45}{2}$ ÷ $\frac{30}{1}$ x 100%

Change the division sign to multiplication and reciprocate the fraction.

Percentage (walking) = $\frac{45}{2}$ x $\frac{1}{30}$ x 100%

Note: The zero in 30 and 100 cancels each other. 3 divides itself once and 45, 15 times. 2 divides itself once and 10, 5 times.

Percentage (walking) = 15 x 1 x 5%
Percentage (walking) = 75%

Percentage = Amount/Total Amount x 100

Percentage left = Amount Left/Total Amount x 100

Amount Left = GH₵ 200.00 - GH₵ 83.00 = GH₵ 117

Percentage Left = 117/200 x 100% = 58.5%

Method I

Using formula

Total mangoes = 20

Percentage rotten = 20%

Number rotten = $\frac{20}{100}$ x 20 = 2 x 2 = 4

Notes:

1. The zeros in 100 and 20 cancel each other
2. The zeros in 10 and 20 cancel each other
3. 2 x 2 = 4

Number rotten = 4

Number not rotten = Total mangoes - Number rotten

Total mangoes = 20

Number not rotten = 20 - 4

Number not rotten = 16

Alternatively,

100% represents the total mangoes

20% rotten

Percentage not rotten = 100% - 20% = 80%

Number not rotten = $\frac{80}{100}$ x 20 = 8 x 2 = 16

Notes:

1. Zeros in 100 and 20 cancel each other
2. Zeros in 10 and 80 cancel each other
3. 8 x 2 = 16

Method II

Using proportionality

100% represents the total mangoes

20% rotten

Percentage not rotten = 100% - 20% = 80%

Total number of mangoes = 20

If 100% = 20

80% = $\frac{\mathrm{80\%\; x\; 20}}{\mathrm{100\%}}$ = 8 x 2 = 16

∴ 16 mangoes not rotten

25% = $\frac{25}{100}$ = $\frac{1}{4}$

Note: 25 divides itself 1 time and 100, 4 times.