If p and r are integers, and p^2 = 20r, then r must be divisible by which of the following?

If p and r are integers, and p^2 = 20r, then r must be divisible by which of the following?

Quiz

Answer/Solution

5

Steps/Work

Ans: D
Solution: for p to be an int 20 r must be whole square of a number.
20r= 5*2*2*r
to make it whole square we need 5
so r can must be divisible by 5y where y is itself a whole square.
so C is the ans