请问prep一题

luningzhao

42.    3744-!-item-!-187;#058&003565
John and Mary own shares of stock in a certain company.  Does John own more shares of the company's stock than Mary?

(1) Mary owns more than 500 shares of the company's stock.

(2) The number of shares of the company's stock that John owns is 400 less than twice the number of shares of the company's stock that Mary owns.
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【答案】C
【思路】問J>M
(1)M>500     ----------------------------------------------------------------------insufficient
(2) J=2M-400  --------------------------------------------------------------------- insufficient
(1)(2)用數字代入 J>M--------------------------------------------------------------- sufficient
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用数字带入也有可能是J<M啊

luningzhao

up

crystalhuang

J-M=M-400>500-400=100>0

luningzhao

J-M=M-400>500-400=100>0

-- by 会员 crystalhuang (2010/5/6 22:22:42)

谢谢，做得有些傻了