In a class of 40 students, 32 offer mathematics, 24 offer...
In a class of 40 students, 32 offer mathematics, 24 offer Physics, and 4 offer neither Mathematics nor Physics. How many offer both Mathematics and Physics?
20
16
8
4
Correct answer is A
Using a venn diagram, let x = number who offer both Maths and Physics. So that (32-x) offer Maths and another (24-x) offer Physics.
(32-x) + (24-x) + (x) + (4 who offer neither) = 40
=> 60 - x = 40
=> -x = -20
Therefore x = 20.