Question

A light bulb consumes

Answer 1

To determine how long it takes to consume, simply take 15,300 watt hours and divide it by the initial rate of 3600 watt hours per day.

Answer 2

The equation you'd use to figure this out is 3600x=15,300. 
"x" represents how many days it'd take. So, just solve for x.

3,600x = 15,300
Divide both sides by 3,600 to get x =4.25

The answer is that it'd take 4.25 days to consume 15,300 watt-hours.