mavesum wrote:A number of light bulbs were purchased to illuminate a gym. However, only 2/3 of them were needed and 160 leftover light bulbs were returned. If only 60% of their cost, or $96, was reimbursed, how much money was spent on illuminating the gym?
In future, please provide the answer choices - you lose a lot of great strategy tips when we don't see them.
We know that $96 represents 60% of the cost of 160 bulbs. We also know that 160 is 1/3 the total number of bulbs purchased; therefore, 320 bulbs were actually used.
If 96 = 3/5(cost of 160), then
cost of 160 = (5/3)96 = 5*32 = $160... in other words, the cost is $1/bulb.
So, we used 320 bulbs, that's $320.
We lost $160 - $96 = $64 on our returns.
Total cost = $320 + $64 = $384
We could have solved more quickly if we recognized that:
Total cost = Cost(160 bulbs) + Cost(160 bulbs) + 40%(cost(160bulbs)) = 240%(cost(160 bulbs))
240%(cost(160 bulbs)) = 4*60%(cost(160 bulbs)) = 4*96 = 384
Lots of other ways we could have played with the fractions as well.
