Find the sum of all whole numbers less than 50 that are multiples of 5 but not multiples of 3.

Step-by-step solution

1. Identify all multiples of 5 less than 50: 5,10,15,20,25,30,35,40,45.
2. Exclude the numbers that are also multiples of 3: 15,30,45.
3. Remaining numbers are: 5,10,20,25,35,40.
4. Add them: 5+10=15, 15+20=35, 35+25=60, 60+35=95, 95+40=135.

Concept tested: Sum of selective multiples

Published 13 October 2026 · How this solution was prepared and checked