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# In a class of 40 students, 32 offer Mathematics, 24 offer Physics and 4 offer ne...

### Question

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?

A) 4

B) 8

C) 16

D) 20

### Explanation:

No of students in class = 40
(M) No of students who offer mathematics = 32 - x
(P) No of students who offer physics = 24 - x
(N) No of students who offer neither mathematics nor physics = 4
(B) No of student who offer both = x
Total no of students = M + P + N + B
40 = 32 - x + 24 - x + 4 + x
40 = 32 + 24 + 4 - x
40 = 60 - x
x = 60 - 40
x = 20

Explanation provided by Mariam

## Discussion (2)

• Mariam

No of students in class = 40
(M) No of students who offer mathematics = 32 - x
(P) No of students who offer physics = 24 - x
(N) No of students who offer neither mathematics nor physics = 4
(B) No of student who offer both = x
Total no of students = M + P + N + B
40 = 32 - x + 24 - x + 4 + x
40 = 32 + 24 + 4 - x
40 = 60 - x
x = 60 - 40
x = 20

• No. of students in class = 40
No. of students who offer Mathematics = 32
No. of students who offer Physics = 24
No. of students who offer neither Mathematics nor Physics = 4
No, of students who offer both Mathematics and Physics = x
32 + 24 + 4 - x = 40
x = 56 + 4 - 40 = 20