Question

Twenty-one students at a school have an allergy to peanuts, shellfish, or both.

 Fourteen students at the school are allergic to peanuts.
 Twelve students at the school are allergic to shellfish.
How many of the students are allergic to both peanuts and shellfish?
A 12
B 7
C 5
D 2

Answer 1

this doesn't make any sense... bc if you add the amount of students allergic to peanuts and the amount of students allergic to shellfish, the number is 24, which is over 21?