rahulprasad90 wrote:

Hello Guys,

Please suggest me an alternative approach to solve this problem.

Q. A solution of X pounds of water and sugar is boiled until 20% of the water content evaporates. Originally y% of sugar was present in the solution. After evaporation, what percentage of the solution is sugar?

a. 100y/(1-y)

b. 80y/(1-y)

c. 75y/(1-y)

d. 100y/80-0.2y

e 100y/80+0.2y

The answer in the guide is (d.)

Assume values when the options have a variable.

Say, x is 100 pounds. Say y% is 50% i.e. the solution had 50 pounds of sugar and 50 pounds of water.

20% water evaporates so 20/100 * 50 = 10 pounds of water evaporates leaving 40 pounds of water.

%age of sugar solution = 50/(50+40) * 100 = 55%

Put y = 50 in the options. Options (A), (B) and (C) make no sense since they will have a negative denominator. Option (E) gives 55% when you put y = 50.

Answer (E)

And yes, please post Problem Solving questions in the the PS forum.

_________________

Karishma

Veritas Prep GMAT Instructor

Learn more about how Veritas Prep can help you achieve a great GMAT score by checking out their GMAT Prep Options >