If k is a positive integer, is k the square of an integer?
(1) k is divisible by 4.
(2) k is divisible by exactly four different prime numbers.
Ans: (E)
(1) 8 is divisible by 4, but it's not a square of an integer.
16 is divisible by 4, but it's a square of an integer.
----> insufficient
(2) if it's exactly four different prime numbers,
K= a *b*c*d where a,b,c, d are different prime numbers.
my question here:
does that mean K can be a value of (a^2)*(b^2)*(c^2)*(d^2) ???
