The numbers in which of the following pairs do NOT have a pair of distinct prime divisors in common?  Choices
A) 10 and 20 B) 12 and 18 C) 24 and 16 D) 21 and 63 E) 22 and 88
16 has only the prime 2 (16=2^4) in its prime factorization, so it can not have a PAIR of distinct prime divisors in common with ANY of the numbers.   The answer is 24 and 16.
<result>C</result>
The numbers in which of the following pairs do NOT have a pair of distinct prime divisors in common?