A clock store sold a certain clock to a collector for 30 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 60 percent of what the collector had paid. The shop then sold the clock again at a profit of 90 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 $150, for how much did the shop sell the clock the second time?
Options: A) $1010.46 B) $505.23 C) $2020.92 D) $800.46 E) $1515.69
Now, in the question above, lets say the original cost of the clock to store was C$ and then it sold the same to the collector at 30% profit.   This means the clocks' selling price was C (1.3) and this becomes cost price for the collector.   Now, when the collector tries to sell the same clock to the store, the store buys it for 60% the price at which the collector bought it.   Thus, you get = 1.3*0.6*C = 0.78 C   Furthermore, the store sells the clock for the second time for 90% profit and thus the selling price of the clock becomes = cost price of the clock for the store at buy-back * 1.9 = 1.9 * 0.78 C   Finally given that C - 0.78 C = 150 ----&gt; C = 681.82$   Thus, the cost of the clock the second time around = 1.9*0.78 C = 1.9 * 0.78 * 681.82 = 1010.46$. Hence $1010.46 is the correct answer.
<result>A</result>
A clock store sold a certain clock to a collector for 30 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 60 percent of what the collector had paid. The shop then sold the clock again at a profit of 90 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 $150, for how much did the shop sell the clock the second time?