If a "Junior Class" has 50 students in total and 25 take french, 15 take latin, and 10 take both you find the answer be using subtraction and addition.
Problem Solved:
50 - (25 + 15 + 10)
= 50 - 50
= 0
So, your answer is correct. Since all students take at least one language class (French, Latin, or Both) the probability that the chosen student takes none of those because all students take at least one. Hope this helped!
Answer: a. 0 (neither)