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Expert replies
by manasi_sh » Fri Oct 05, 2007 4:03 am
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) ¾

plz explain..
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Source: — Problem Solving |

by kajcha » Fri Oct 05, 2007 4:10 am
suppose the original solution is x unit and y units are replaced

so, we can write

(x-y)*0.4 + 0.25*y = 0.35*x. Solve for

y/x = 1/3 ANS
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