rmadmit wrote:
Can anyone please explain how the cost of one bulb has been calculated?
Let's take it step by step.
Consider the Quantity of bulbs =X
2/3 of bulb used, it means 1/3 of the bulb left unused.
We have been told that left = 16, then............. (1/3)(X)= 160.........> X=480
It means 320 bulb used in gym
Now let's find price/bulb
consider cost/bulb= C
We have told that '60% of the COST of LEFT unused bulbs' have been returned, which equals to $96.
Cost of left unused bulbs= 160C
60% of Cost of left unused bulbs = 0.6 * 160 C= $96
96C =96........... means C = $1
Total cost of bulbs ONLY used for gym = $320
However, there is still 40% of cost LEFT bulbs = $64 which not returned and incurred in total cost.
Total cost= 320 + 64= $384
Answer: E