The answer is 11400 seconds.
First you have to find out how many seconds are in one hour. To do this you have to multiply 60 by 60, because there are 60 minuets in one hour, and 60 seconds in one minute. When you do this you get 3600 seconds.
Now you have to multiply it by three, because there are three hours. When you do this you get 10800 seconds.
Now you have to find out how many seconds are in 10 minuets. You multiply 60 by 10, because there are 60 seconds in one minute. When you do this you get 600.
Now all you have to do is add 10800 and 600, and that is you get 11400 seconds.