Question

If an electric kettle uses

2 1/4 kilowatts of energy in 1.5 hours, how much energy will it use in 3.5 hours?

Answer 1

The energy used in 3.5 hours = 5.25 kilowatts

Explanation:

Energy used by electric kettle:

• 
  `2(1)/(4)=(9)/(4)=2.25` kilowatts

Time taken by electric kettle:

• 1.5 hours

Electric kettle's rate in kilowatts per hour can be calculated by dividing the spent energy i.e. 2.25 kilowatts by the time taken i.e. 1.5 hours.

Therefore,

Electric kettle's rate = 2.25 kilowatts / 1.5 hour

= 1.5 kilowatts per hour

Thus, the energy used in 3.5 hours = 1.5 × 3.5

= 5.25 kilowatts

Therefore, the energy used in 3.5 hours = 5.25 kilowatts