-5 = $\frac{-5}{1}$ hence is a rational number

$\sqrt{4}$ = 2 = $\frac{2}{1}$ hence is a rational number

3$\frac{3}{4}$ = $\frac{\mathrm{3\; x\; 4\; +\; 3}}{4}$ = $\frac{\mathrm{12\; +\; 3}}{4}$ = $\frac{15}{4}$ hence is a rational number

$\sqrt{\mathrm{90}}$ = 9.4868 hence not a rational number since can't be expressed as a fraction of two integers.

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 = $\frac{86}{2}$ = 43