X and Y are two sets such that n(X) = 15, n(Y) = 12 and n{X ∩ Y} = 7. Find ∩{X ∪ Y}
-
A.
21 -
B.
225 -
C.
15 -
D.
20
Correct Answer: Option D
Explanation
n(X ∪ Y) = n(X) + n(Y) − n(X ∩ Y)
= 15 + 12 − 7
∴ n(X ∪ Y) = 20
There is an explanation video available below.