DS A store purchase 20 coats that each cost an equal amount and then sold each of the 20 coats at an equal price. what was the store's profit on the 20 coats? 1) If the selling price per coat had been twice as much, the store's gross profit on the 20 coats would have been $2400 2) If the selling price per coat had been $2 more, the store's gross profit on the 20 coats would have been $440 答案是B， 我选D,但其实我根本也不明白题目到底要干什么， 问what was the profit on 那20件 coats？ 两个条件不是都告诉我们profit on 那20件coats了吗？
还有第一个条件， 什么叫price per coat had been twice as much? as much as 什么啊？ as much as cost?怎么理解啊，这话什么意思？这题神马意思啊？ 请各位帮忙分析了！ （ btw,题目第一句好像也又语法错误，coats的定语从句里that each cost， each 做主语，谓语应该单数，应该是each costs吧？）
Coat was bought at price $x and sold at price $y. Ask for the profit = 20*(y-x)
1) 20*(2y-x) = 2400. Two unknowns, one equation, not sufficient to sove both x and y, and not sufficient enough to sove (x-y). 2) 20*(y+2-x) = 440. Two unknowns, one equation, not sufficient to solve both x and y, but sufficient enough to solve (x-y)
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发表于 2011-4-9 20:54:28
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