Question 1179783
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<pre>

15 minutes per day, 30 days per month is  {{{30/4}}} = 7.5 hours  per month.


Hence, the electrical  power of the water heater is


    {{{18/7.5}}} = 2.4 Kw = 2.4 kilo-watts.    <U>ANSWER</U>
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Solved, answered and explained.