Percentage Q37

37.	B as a percentage of A is equal to A as a percentage of (A + B). Find B as a percentage of A.

	A.	62%
	B.	73%
	C.	41%
	D.	57%

Answer  - (A)
Solution:
From the question stem, we know BA=(AA+B)   --------------- (1)

As B is a percent of A, let us assume B=Ax
Then, equation (1) can be re-written as x=(11+x) 
=>  x(1+x)=1

After this step, trial and error works best. The solution is 62%, answer choice (A) is the correct one.

Alternatively, solving, we get x2+x−1=0
=> x=(−1+52) or x=(−1−52)
So, x=(−1+52)=1.242

Or 0.62 = 62%