Question

in a school there are 20 teachers who teach mathematics or physics of these 12 teach both physics and mathematics how many teach physics ​

Answer 1

Number of teachers who teach math or physics =n(M∪P)=20

Number of teachers who teach math = n(M)=12

Number of teachers who teach math and physics =n(M∩P)=4

Find : Number of teachers who teach physics =n(P)=?

Solution :

n(M∪P)=n(m)+n(P)−n(M∩P)

20=12+n(P)−4

20−12+4=n(P)

n(P)=12

Hence 12 teacher teach the physics .

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Answer 2

Answer:

12 is the answer.......