Of the 60 animals on a certain farm, 2/3 are either pigs or cows. How many of the animals are cows?
(1) The farm has more than twice as many cows as it has pigs
(2)The farm has more than 12 pigs
选C吧, pig+cow共40.
1) c>2p-----单独选项,有很多可能 p=1 c=39 ;p=2 c=38....
2) p>12---- 单独选项,有很多可能,
一起考虑1 2,只能取p=13 c=27.
由题意可设 pig 为x, cow为nx (n大于等于2)
则有 x+nx=40 即x= 40除以n+1
因为n+1大于等于3 即x小于等于3分之40,同时x又大于12即3分之36 所以x只能取13,此时nx只能取27
即pig 13;cow 27
欢迎光临 国际顶尖MBA申请交流平台--TOPWAY MBA (http://forum.topway.org/) | Powered by Discuz! 7.2 |