Nandu uses 60W bulbs. He plans to replace 3 bulbs per day with 15W bulbs for 10 days. How many watts does he save in total?

Step-by-step solution

1. Old bulb power = 60W, new bulb power = 15W.
2. Power saved per bulb = 60 – 15 = 45W.
3. Number of bulbs replaced per day = 3.
4. Daily savings = 45 × 3 = 135W.
5. Number of days = 10.
6. Total savings = 135 × 10 = 1350 watts.
7. Nandu saves 1350 watts in total.

Concept tested: Energy saving calculation

Published 10 October 2026 · How this solution was prepared and checked