SAT Math Multiple Choice Practice Question 361: Answer and Explanation
9. If l, m, and n are positive integers greater than 1, , and , then which of the following must be true?
Correct Answer: A
A If and both land mare integers, then m must be either 1, 3, 7, or 21. If , however, then m must also be a factor of 39, so it must be 3. Therefore, and , so .