I recently came across this question in a chemistry text book. It's seems relatively simple but I get an answer different to the one in the book and can't understand why.

A 2000MW power station has an energy output of 2000MJ/s. How long would it take to generate 3.39x1016J of energy?

First, I converted joules to mega joules giving: 3.39x10^10J

Then, 3.39x10^10 / 2000

Giving, 16950000 s.

Which works out at about 196 days.

The answer the book gave was 175 days.

Thanks for any help.