Question

he school has 800 students with 20 students on the gymnastic team and 10 students on the chess team (including 3 students who are on both teams). How many students in the school are not members of either the gymnastic team or the chess team?

Answer 1

There are 17 members who are only in gymnastics, 7 who are only in chess, and 3 who are in both.
17+3+7=27
800-27=773