Amicrowave oven has a power requirement of 1238 w. a frozen dinner requires 6.9 minutes to heat on full power. (a) how much electrical energy in (kwh) is used?
(b) if the cost of electricity is 12 cents per kwh, how much does it cost to heat the dinner?

(a) 142.37 kWh (b) 1708.44 cents

Explanation:

It is given that the microwave has a power requirement of 1238 W

The frozen dinner takes 6.9 minutes to heat

So time t =6.9 minutes

(a) The total energy used = power ×time = 1238×0.115=142.37 kWh

(B) The cost of the electricity is 12 cents per kWh

So total cost = 12×142.37=1708.44 cents

your answer is c! hope this : )