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| Question 340307:  If n and p are different positive prime numbers, which of the integers n^4, p^3 and np has (have) exactly 4 positive divisors?
 (A) n^4 only
 (B) p^3 only
 (C) np only
 (D) n^4 and np
 (E) p^3 and np
 
 Could you please explain the above problem.
 Answer by AnlytcPhil(1808)
      (Show Source): 
You can put this solution on YOUR website! If n and p are different positive prime numbers, which of the integers n^4, p^3 and np has (have) exactly 4 positive divisors? 
 n4 = nnnn has divisiors 1,n,nn,nnn,nnnn that's 5
 p3 = ppp has divisors 1,p,pp,ppp, that's 4
 np has divisors 1,n,p,np, that's 4
 So the answer is
 (E) p3 and np
 Edwin
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