Problem:
Which pair of numbers does NOT have a product equal to 36?
Answer Choices:
A. {−4,−9}
B. {−3,−12}
C. {21​,−72}
D. {1,36}
E. {23​,24}
Solution:
21​×(−72)=−36.
Answer: C​.
The problems on this page are the property of the MAA's American Mathematics Competitions