M and N are two subsets of the universal set (U). If n(U) = 48,...

M and N are two subsets of the universal set (U). If n(U) = 48, n(M) = 20, n(N) = 30 and n(MUN) = 40, find n(M \(\cap\) N)

The correct answer is: D

Let n(M \(\cup\) N \) = x

Then 20 - x + x + 30

- x = n(M \(\cup\) N)

50 - x = 40

50 - 40 = x

10 = x

x = 10

Hence, n(M \(\cup\N)' = 8 + (20 - 10) + (30 + 10)

= 8 + 10 + 20

= 38