72% of the students of a certain class took Biology and 44% took Mathematics. If each student took at least one of Biology or Mathematics and 40 students took both of these subjects, the total number of students in the class is:

n(A) = Biology students = 72%
n(B) = Mathematics students = 44%
Total students = n(A ∪ B) = 100%
∴ 100% = 72% + 44% - n(A ∩ B) = 116% - n(A ∩ B)
∴ n(A ∩ B) = 16%
⇒ number of students studying both subjects = 40
∴ Let the total number of students be P
Now, according to the question,
16P/100 = 40
∴ P = 250