In an interview of 50 math majors,

Question

12 liked calculus and geometry
18 liked calculus but not algebra
4 liked calculus, algebra and geometry
25 liked calculus
15 liked geometry
10 liked algebra but neither calculus nor geometry
2 liked geometry and algebra but not calculus.
Of those surveyed, how many liked calculus and algebra?

Answer 1

If you want the number that liked both calculus and algebra, there is only one category that fits that description.

I hope this helps.