Francisco P. answered • 10/04/14

Rigorous Physics and Math Tutor

Eliminating the 12 students that do not like either salad or tofu, you will have 40 students that like either or both.

Tofu | Tofu & Salad | Salad

x 10 13

x + 10 + 13 = 40

x = 17 students who only like tofu.