There are 100 students in 11th grade at john d'obryant school of math & science in boston. 60 like basketball and 70 like tennis and 10 play on varsity teams. all of them like at least one sport. how many like both tennis and basketball?
I think 70 because playing on a varsity, i think, means to play both sports. So I added 10 to the number of students that play basket ball, which is also equal to the number of students that like tennis.
