The heater element of an electric kettle has a constant resistance of 105 and applied voltage of 240V. 1.Calculate time taken to raise the temperature

The heater element of an electric kettle has a constant resistance of 105Ω and applied voltage of 240V.

1.Calculate time taken to raise the temperature of one litre of water from 15oC to 90oC assuming that only 80% of the power input to the kettle is usefully employed.

2.If the water equivalent of the kettle is 150g, find how long it will take to raise a second litre of water through the same temperature range immediately after the first time.

Pleae show all steps,I have calculated the answers but not sure of second answer