At Mallard High School there are three intramural sports leagues: football, basketball, and baseball. There are 427 students participating in these sports: 128 play on football teams, 291 play on basketball teams, and 318 play on baseball teams. If exactly 36 students participate in all three of the sports, how many students participate in exactly two of the sports?
So I'm not gonna give you the answer here (because I haven't calculated it yet), but in these types of problems, I think you should use a Venn diagram.
Make three circles and label them for Football, basketball, and baseball. Where all three circles overlap, put the number 36 in it. And put 128, 291, and 318. The reason that the sum of these numbers goes over 427, is because some of these people play other sports or all 3 sports.