Problem:
If a∗b=a+ba×b​ for a,b positive integers, then what is 5∗10?
Answer Choices:
A. 103​
B. 1
C. 2
D. 310​
E. 50
Solution:
5∗10=5+105×10​=1550​=5×35×10​=310​.
Answer: D​.
The problems on this page are the property of the MAA's American Mathematics Competitions