[quote="salma"]Is n an integer?
(1) n^2 is an integer
(2) square root of n is an integer
The answers says that from (2) we can know that n is an integer but not from (1). I cannot think of a non integer which square root is an integer?
Thx[/quote]

1 - insufficient. Knowing n^2 is an integer does not tell us anything
about n. N could be 2, n could be sqrt(2). Both will yield integers for n^2

2 - sufficient. If sqrt(n) is an integer, then n is definitely an integer.

Hope this helps

salma wrote:Is n an integer?
(1) n^2 is an integer
(2) square root of n is an integer
The answers says that from (2) we can know that n is an integer but not from (1). I cannot think of a non integer which square root is an integer?

Am I missing stg?

Thx

That is exactly the reason why answer is (B)