If A and B are two sets such that `n(A) = 15, n(A cup B) = 40 and n (A cap B) = 5`, then find each of the following :
(i) `n (B)`
(ii) `n (A- B)`
(iii) `n (B-A)`

Explanation

(i) From
`n(A cupB)=n(A)+n(B)-n(AcapB)`
`40=15+n(B)-5`
`rArr n(B) = 30`.
(ii) `n(A-B)=n(A)-n(AcapB)`
`=15-5=10`
(iii) `n(B-A)=n(B) - n(Acap B)`
`=30 - 5 = 25`.