Taran wrote:@Sumit: I agree that the problem should not be (35^2-1)/K, but rather be 35^2 - 1/k. Please help me derive the answer to the later. I tried to solve it this way:

35^2-1/K ---> ((5x5x7x7xK)-1) /K

Now i can see that 5x5x7x7xK is a multiple of K and is therefore always divisible by K. But when you subtract 1 from it, it cannot be divisible by K. Thus for any integer value of K, i dont see that the overall expression will lead to an Integer.

Please help me. I guess i'm missing something here !!!!!
Taran the problem becomes very simple in the second case (35^2)- (1/k) can only be an integer if k=1 or -1 nothing else would make it as an integer if k is already an integer.
Cheers...

neoreaves wrote:If k is an integer, and 35^2-1/k is an integer, then k could be each of the following, EXCEPT

(A) 8(B) 9(C) 12(D) 16(E) 17

rockeyb wrote:Using the formula (x^2 - y^2 ) = (x+y)(x-y)

35^2 -1 = 35^2 - 1^2

We can write this as (35+1)(35-1)= 36 x 34

So the question becomes (36 x 34)/ k = int .

K is an integer .

so only number that can not divide completely is 8 .

[spoiler]Ans : A .[/spoiler]

whats the OA ?