Are some goats not cows?
(1) All cows are lions
(2) All lions are goats
Please help to understand this question!
-GK
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Goat Cow Lion
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GmatMathPro
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I'm guessing this is not from an official source.....
First, forget everything you thought you knew about goats, cows, and lions. Then,
Are some goats not cows?
Statement 1: All cows are lions. This tells us nothing about how goats relate to cows. INSUFFICIENT.
Statement 2: All lions are goats. This tells us nothing about how goats related to cows. INSUFFICIENT.
Statements 1 and 2: Together, we know that all cows are lions, and all lions are goats, therefore all cows are goats. INSUFFICIENT. the best way to examine this, that i know of, is to draw circles representing the sets. We know that the set of cows is entirely contained within the set of lions, which in turn, is entirely contained within the set of goats. So, there could some goats who are just goats, but not lions, or cows. There could be some goats who are goats, lions, but not cows, and there could be animals that are all three. In this case the answer would be yes, there are some goats that are not cows. However, it could be that all three sets coincide exactly. That is, every animal under consideration here is a goat, lion, and cow. In which case the answer would be no, there are not some goats that are now cows.
In a case like this, you may want to rewrite the problem as follows:
Are some G not C?
1) All C are L
2) All L are G
That way you don't let your own preconceived notions about what is or is not a goat get in your way.
However, I highly doubt you'd see something like this on a GMAT Data Sufficiency question. Remember they say that you should use your knowledge of mathematics and everyday facts(like the number of days in July or the definition of the word counterclockwise) to solve the problems. I think you could make a pretty strong case that the fact that goats and cows are different things is an everyday fact.
Anyway, the answer is E
First, forget everything you thought you knew about goats, cows, and lions. Then,
Are some goats not cows?
Statement 1: All cows are lions. This tells us nothing about how goats relate to cows. INSUFFICIENT.
Statement 2: All lions are goats. This tells us nothing about how goats related to cows. INSUFFICIENT.
Statements 1 and 2: Together, we know that all cows are lions, and all lions are goats, therefore all cows are goats. INSUFFICIENT. the best way to examine this, that i know of, is to draw circles representing the sets. We know that the set of cows is entirely contained within the set of lions, which in turn, is entirely contained within the set of goats. So, there could some goats who are just goats, but not lions, or cows. There could be some goats who are goats, lions, but not cows, and there could be animals that are all three. In this case the answer would be yes, there are some goats that are not cows. However, it could be that all three sets coincide exactly. That is, every animal under consideration here is a goat, lion, and cow. In which case the answer would be no, there are not some goats that are now cows.
In a case like this, you may want to rewrite the problem as follows:
Are some G not C?
1) All C are L
2) All L are G
That way you don't let your own preconceived notions about what is or is not a goat get in your way.
However, I highly doubt you'd see something like this on a GMAT Data Sufficiency question. Remember they say that you should use your knowledge of mathematics and everyday facts(like the number of days in July or the definition of the word counterclockwise) to solve the problems. I think you could make a pretty strong case that the fact that goats and cows are different things is an everyday fact.
Anyway, the answer is E
