Problem:
For how many three-digit whole numbers does the sum of the digits equal
Answer Choices:
A.
B.
C.
D.
E.
Solution:
Since the sum of the three digits must equal and , it follows that at least one of the digits must be a . If only one digit is , then the other two digits add up to and are each . If two digits are , then the other digit is . There are six numbers that meet the requirement:
Answer: .
The problems on this page are the property of the MAA's American Mathematics Competitions