let x be the fraction replaced. if x is the fraction then the total is 1.ddm wrote:A certain quantity of 40% solution is replaced with 25% solution such that the new concentration is 35%. What is the fraction of the solution that was replaced?
(A) 1/4
(B) 1/3
(C) 1/2
(D) 2/3
(E) 3/4
Your Answer : D
Actual Answer : B
(1-x)*40 + x*25 = 35
40 - 40x + 25x = 35
5 = 15x
x = 1/3
