There are 60 boys to make up the boys' teams and 40 girls to make up the girls' teams.
We are also told that the teams should be the same size.
This means that irrespective of the number of teams, each team should contain the same number of players.
Thus, the largest number of people that can be placed on a team is;
The highest common factor ;
The HCF is 10 x 2 = 20, therefore;
The largest number of people that can be placed on a team is 20.