Because everyone donated the same amount, the total amount donated by the two classes is the same, so the number of people in the two classes is the same. So m+ 1 1=9+n,

That is, n=m+2.

Assuming that everyone's donation is Y, then Y = (Mn+9m+ 1 1 n+145) divided by (m+11). Substitute n=m+2 into this formula. You can get Y=(mm+22m+ 167) divided by (m+ 1 1).

Simplify this formula to get y = m+11+46/(m+11).

Because y is an integer and 46/(m+ 1 1) is also an integer, m+ 1 1 can only be 1, 2,23,46. one of them

So m= 12 or 35.

Substitute m= 12 or 35 to get Y=25 or 47.

So the answer is 25 or 47.