Xbond wrote:Hi guys
Who knows the answer for sure ?
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 at it has pigs
(2) The farm has more than 12 pigs
I hesitated between C and E
You're certainly correct that neither statement alone is sufficient.
A great way to approach data sufficiency is to pick numbers. If you can pick numbers that satisfy the rules you're given and still get more than 1 answer to the question, then you don't have enough information.
(1) c > 2p
We have a total of 40 cows and pigs (2/3 of 60). If c > 2p, we could have:
39 cows and 1 pig
or
38 cows and 2 pigs
(or lots of other breakdowns).
Since we can get more than one value for "number of cows", (1) is insufficient.
(2) p > 12
We could have 27 cows and 13 pigs
or
13 cows and 27 pigs
(or lots of other breakdowns).
Since we can get more than one value for "number of cows", (2) is insufficient.
Together:
from (2), we know that the smallest value we can choose for p is 13. If we have 13 pigs, we have 27 cows.
let's try to increase the number of pigs to 14. If we have 14 pigs, we have 26 cows. However, now we've violated (1) that says that we need more than twice as many cows as pigs.
So, to satisfy both rules, we know that p=13 and c=27. We have a definite value for the number of cows, so together the statements are sufficient: choose (C).
