求解Prep上的一题

quting

Of the 60animals 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 cows as many as it has pigs.
(2)The farm has more than 12 pigs.  

答案是C，怎么也算不出这个结果，望高人指点。

flyingbunny

60*2//3=40
C+P=40

条件1 C>2P insuff
条件2 P>12 insuff
1+2
只有
P=13
C=27

if P>13, for example P=14, C>28, then C+P>40

故选C