请教prep数学一道DS题

amy0208 · 发表于 2010-10-18 19:38:59

of the 60 animals on a farm,2/3 are either pigs or cows. How many of 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.

答案是C，可我怎么觉得两个加在一起也不行呢。求NN解答。顺便给翻译下题目吧，1和2的条件到底是什么意思，怀疑自己理解有误

danoulini · 发表于 2010-10-18 19:54:36

已知：cow + pig = 40

1) cow > 2 * pig

=> 40 - pig > 2 * pig
=> p < 40/3
=> p <= 13
=> insufficient

2) pig > 12
=> insufficient

1)+2)
=> pig = 13
=> cow = 27
=> sufficient

amy0208 · 发表于 2010-10-18 20:05:17

已知：cow + pig = 40

1) cow > 2 * pig

=> 40 - pig > 2 * pig
=> p < 40/3
=> p <= 13
=> insufficient

2) pig > 12
=> insufficient

1)+2)
=> pig = 13
=> cow = 27
=> sufficient

-- by 会员 danoulini (2010/10/18 19:54:36)

谢谢，原来是倍数理解错了，很谢谢你的解答

请教prep数学一道DS题

所属分类: GMAT考试

正在浏览此版块的会员 ()

浏览过的版块