A light bulb consumes 2400 watt-hours per day. How many watt-hours does it consume in 3 days and 18 hours?

Hi!!
The answer is 9,00 watt-hours

Proofs:

24 hours in a day
The light bulb consumes 2400 watt-hours a day.

2400/24=100

Therefore: the light bulb consumes 100 watt-hours an hour.

3 days=72 hours

72+18=90

Therefore: 3 days and 18 hours=90 hours.

100*90=9,000

Therefore: a light bulb will consume 9,000 watt-hours in 3 days and 18 hours