I cannot see this being a GMAT problem - how is one supposed to calculate 1- [1/(.92*1.2)] without a calculator? Even with using fractions I get 13/138 which is also not easily solved.
Agree.. this calculation goes tough. Any simpler way to avoid that 92 & 12 factor?
My approach is
S = number of students
P = Price
Q = Quantity of food consumption.
C = total cost
==> C = S*P*Q
One way to solve this kind of question is plug in numbers.
Assume: before we have 100 students, P = $10 ==> C = 100*10*Q = 1000*Q
After: we have 92 students, P = $12 ==> C' = 92*12*Q' = 1104*Q'
==> 1104*Q' = 1000*Q
==> Q' = 1000/1104*Q = (1 - 104/1104)*Q
==> Q' = Q - 104/1104*Q
The red part is the decrease of food consumption. We can guess 104/1104 ~ 9.4%
(The ONLY option < 10%) --> E is answer.
Hope it helps.
Please +1 KUDO if my post helps. Thank you.
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