# Question #5c599

Mar 11, 2017

Energy is power x time, or $E = p \times t$

#### Explanation:

To get the energy in kWh, we need to express the power in kW:

$p = 4 \times 100 W = 400 W = 0.4 k W$ (remember $1 k W = 1000 W$)

If all this is used for 10 hours a day, and september has 30 days, then the time factor is:

$t = 10 h \times 30 = 300 h$

Putting these together we get:

$E = p \times t = 0.4 k W \times 300 h = 120 k W h$