Solution: let the number of people who scored three goals be X and the number of people who scored four goals be Y.

A set of binary linear equations can be obtained from the meaning of the question.

3x+4y+ 10=3.5(x+y+2)

0+2+2 * 7+3x+4y = 2.5( 1+2+7+x+y)

The solution is x=9 y=3.

So the number of people who scored three goals is nine, and the number of people who scored four goals is three.