Question 103

If 60% of (x — y) =45% (x + y) and y = k% ofx, then 21% of k is equal to

Solution

Given that $$\dfrac {60}{100} \times (x-y) =\dfrac {45}{100} \times (x+y) $$

$$ \Rightarrow 4 (x-y ) = 3(x+y) $$

$$\Rightarrow 4x-4y= 3x+3y $$

$$\Rightarrow x= 7 y $$

$$\Rightarrow \dfrac{y}{x } = \dfrac{1}{7} $$

and $$ y= \dfrac{k}{100} \times x$$

$$\Rightarrow k = \dfrac {100}{x} y $$

$$\Rightarrow k = \dfrac {100}{7}$$

hence 21 % of K = $$\dfrac{21}{100} \times \dfrac{100}{7} $$

$$\Rightarrow 3 $$ Ans

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