Problem:
There are many two-digit multiples of , but only two of the multiples have a digit sum of . The sum of these two multiples of is
Answer Choices:
A.
B.
C.
D.
E.
Solution:
The two-digit multiples of are:
Only and have digit sums of . The sum of and is .
Answer: .
The problems on this page are the property of the MAA's American Mathematics Competitions