Is integer x square of an integer?
1) Sum of all the factors of x is odd
Just this knowledge is sufficient to eliminate this choice
Logically if only prime factor is 2, the factors will always be odd..If x is 2, factors are 1 and 2, and sum = 1+2=3. 2 is not a square
If x is 4, factors are 1, 2 and 4, and sum = 1+2+4=7. 4 is a square.
Insuff.
2) \(x = a^p*b^q\) where a and b are prime numbers and, p and q are odd integers
If a and b are prime numbers, and their power p and q are odd, the number, x, can never be square of any integer.
Even if p and q are same, \(x = a^p*b^q=(ab)^p\)..
We require a EVEN power for the number to be a square. Thus, answer is always NO..
B
GMATinsight, please look into your OA. It cannot be E. B will be the answer
Second statement doesn't mention that the Prime numbers are distinct... so \(x =2^3*2^5\) is also acceptable making the number as perfect square.