Is there a question here? I can't see it!
Simplify the integrands by polynomial division.


Now computing the integrals is trivial.
5.

where we use the power rule,

and a substitution to integrate the last term,

8.

using the same approach as above.
The least common multiple is 96
60 divide dos by 15 is 4, so it takes 4 minutes for each person to empty it.
25 x 4 = 100, so the answer would be 100 minutes.