A clock store sold a certain clock to a collector for 20 percent more than the store had originally paid for the clock. When the collector tried to resell the clock to the store, the store bought it back at 50 percent of what the collector had paid. The shop then sold the clock again at a profit of 80 percent on its buy-back price. If the difference between the clock's original cost to the shop and the clock's buy-back price was $100, for how much did the shop sell the clock the second time?
Assume numbers and then use ratios to fit them in with the actual numbers.
Say the store bought the clock for $100 and sold it to the collector for $120. The store bought back from the collector for $60 and sold it back at $60*18/10 = $108
Here, difference between original cost ($100) and buy back price ($60) is $40. But actually it is given to be $100 which is 2.5 times 40. So the shop sold the clock a second time for $108*2.5 = $270
Veritas Prep | GMAT Instructor
Get started with Veritas Prep GMAT On Demand for $199
Veritas Prep Reviews