There are 35 teachers in a school, who teach either Mathematics or Physics. Of these, 23 teach Mathematics and 19 teach Physics. How many teach both Mathematics and Physics?
1
4
2
7
3
9
4
Cannot be determined.
There are 35 teachers in a school, who teach either Mathematics or Physics. Of these, 23 teach Mathematics and 19 teach Physics. How many teach both Mathematics and Physics?