Alaptop computer uses 78.0 w of power. if it runs for 10.0 minutes how much energy does it use?

Power consumed = P = 78.0 W
Time taken = t = 10 minutes
Energy consumed = E = ?

The power, energy and time are related by the following equation:

P = E / t 

Using the values, we get

78 = E/t

So,

E = 780

This means, 780 Joules of energy was used during the 10 minutes