A store purchased 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 gross 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 $2,400.
(2) If the selling price per coat had been $2 more, the store's gross profit on the 20 coats would have been $440.
Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
EACH statement ALONE is sufficient.
Statements (1) and (2) TOGETHER are NOT sufficient.
错因:不明白题意
关键:虚拟语气
(1) 是不充分的。设进价为每件$x,售价为每件$y,题目要求20(y-x)。(1) 只说了20*(2y-x)=2400,只能求出2y-x,求不出y-x。
(2) 是充分的。(2) 的意思是20*((y+2)-x)=440,那么20*(y-x)当然就是$400了。
OK 又掉坑里面了。。。
就是没看懂,但是你可以看懂,不要怕,看着算下去才行。
设卖价为x,买价为y,要求200(x-y)
条件二得200(x+2-y)=440直接求出profit
看清楚要求啥
题目C和P都是未知数
条件(1)、(2)所给出的selling price per coat其实都不是其真正的selling price,只是告诉你这个价格变成了XX后,gross profits会变成多少。所以就要求出真正的selling price 和cost per coat是多少。从而求得20*(S-C)
(1):如果S=2c,代入20*(S-C),得到该条件下的总利润=20*(2c-c)=2400,这里必须把S替换成2c,因为2400是在S=2c下才成立的利润,而非真正的s/c。
(2):如果S=s+2,代入20*(S-C),得到该条件下的总利润=20*(s+2-c)=440,这里能得出20(s-c)=400
设卖价为x,买价为y,要求200(x-y)
条件二得200(x+2-y)=440直接求出profit
看清楚要求啥
只需要求gross profit,那么只要知道P-C的值就可,不需要知道P&C分别是多少!
条件2sufficient的证据是: 因为每一件比原来贵20元,总共20件,所以贵了40元, 所以profit=440-40=400元
而条件1中
(2) p+400-C=440
g=p-c=440-400
这种题真的很惊喜。。。
问题:20*(SP-C)=?
条件2:SP+2-C=440/20
推出SP-C=20
20*20=400
错把条件1看成selling price 是cost 的两倍..审题不仔细
20(2Y-X)=2400 得不到Y-X的具体数值!
条件二就充分的理由是 20(y+2)-20x=440; 也就是 20y+40-20x=440;每样加2块钱之前就是 440-40=400。所以400就是 store 的 gross profit。