Respuesta :

Answer:

The energy used in 3.5 hours = 5.25 kilowatts            

Step-by-step explanation:

Energy used by electric kettle:  

  • [tex]2\frac{1}{4}=\frac{9}{4}=2.25[/tex] 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                        

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