Suppose there are x+8 people in Class A, x+4 people in Class B and X people in Class C.

There are Y peaches in Class A, y+3 peaches in Class B and y+8 peaches in Class C..

Then multiply by (x+8)*y-(x+4)*(y+3)=3. A is three more than B.

(x+4)*(y+3)-x*(y+8)=5 B is five more than c.

It is concluded that class A 19, class B 15 and class C 1 1 person.

Please use O(∩_∩)O if you are satisfied.