dzyubam wrote:
A number of light bulbs were purchased to illuminate a gym. However, only \normal\frac{2}{3} of them were needed. The extra 160 light bulbs were returned. 60% percent of their cost, or $96, was reimbursed. How much money was spent on illuminating the gym?
(A) 360
(B) 320
(C) 384
(D) 364
(E) 160
Source: GMAT Club Tests - hardest GMAT questions
(A) 360
(B) 320
(C) 384
(D) 364
(E) 160
[Reveal] Spoiler: OA
C
Source: GMAT Club Tests - hardest GMAT questions
Solve while reading...
A number of light bulbs were purchased to illuminate a gym. --------> say x
However, only \normal\frac{2}{3} of them were needed. -------> \frac{2}{3}x used ------> means \frac{1}{3}x extra.
The extra 160 light bulbs ------> \frac{1}{3}x=160 therefore x = 480 = total number of bulbs
Extra 160 bulbs Returned 60% percent of their cost, or $96, was reimbursed. ------> 0.6 X 160 X Rate = 96 --------> Rate = 1
How much money was spent on illuminating the gym? --------> Used Bulbs + 40% of unused bulbs --------> 320 + 0.40 X 160 -------> 384 = C