the square of a certain whole number n is n^2. if 60 is a factor of n^2, it's possible that ? is not a factor of n^2
a. 16
b. 25
c. 36
d. 100
60 = 2^2*3*5
So, you know that 2,3,5 are factors of n
So, 4,9,25 are factors of n^2
But, since 16 = 2^4 it is possible that 16 is not a factor of n^2.
In fact, if n=2*3*5=30, n^2=900, which does not have 16 as a factor