Question

There are 12 teachers in a school who can teach Maths or Physics. Out of these, 6 teach Maths and 4 teach Physics and Maths both. Find how many teachers teach Physics ?

Answer 1

Let A = set of reachers who teach Maths and B = set of teachers who teach Physics
Now, `n(A cupB)=12`
`n(A)=6`
and `n(A capB)=4`
Now, `n(A cup B)=n(A)+n(B)-n(A cap B)`
`rArr12=6+n(B)-4`
`rArrn(B)=10`
`:.` No, of teachers who teachers who teach Physics = 10.