If 91% of A is 39% of B, and B is x% of A, then the value of x is:
(a) \displaystyle\frac{200}{3}

(b) \displaystyle\frac{700}{3}

(c) \displaystyle\frac{400}{3}

(d) \displaystyle\frac{500}{3}
{Previously asked in SSC CGL MAINS 2020}

Ans: (b) \displaystyle\frac{700}{3}

Explanation:

ALITER

91% of A = 39% of B

\Rightarrow 7A = 3B [by dividing both side by 13%]

\Rightarrow \displaystyle\frac{\text{A}}{\text{B}} = \displaystyle\frac{3}{7}

Again, B = x% of A

\Rightarrow B = \displaystyle \frac{\text{x}}{100}\times \text{A}

\Rightarrow \displaystyle\frac{\text{A}}{\text{B}} = \displaystyle\frac{100}{\text{x}}

Hence, \displaystyle\frac{3}{7} = \displaystyle\frac{100}{\text{x}}

\qquad\Rightarrow \text{x} = \displaystyle\frac{700}{3}