If 160 kg of dry wood pulp is needed to produce 50 sheets of

gmat_guy666 wrote:If 160 kg of dry wood pulp is needed to produce 50 sheets of paper, how much raw pulp will be needed to produce 200 sheets of paper if raw pulp loses 20 percent of its weight during desiccation?

A)400
B)600
C)640
D)800
E)850

50 sheets of paper are yielded by 160kg of dry pulp.
Thus, 200 sheets of paper -- 4 times the number of sheets -- will be produced by 4 times the amount of dry pulp:
4*160 = 640kg.

We can PLUG IN THE ANSWERS, which represent the required amount of RAW pulp.
When the correct answer choice loses 20% of its weight during desiccation, the result will be 640kg of dry pulp.
To yield 640kg of dry pulp, the amount of raw pulp must be greater than 640.
Eliminate A, B and C.

Answer choice D: 800
After 20% is lost during desiccation, the amount of dry pulp = 800 - 20% of 800 = 800 - 160 = 640.
Success!

The correct answer is D.