Given two sets X and Y such that n(X)=20,n(Y)=25andn(XUY)=40, then n(X−Y)=
A
20
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
5
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
10
No worries! We‘ve got your back. Try BYJU‘S free classes today!
D
15
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
Open in App
Solution
The correct option is D15 Given two sets X&Y such that n(X)=20,n(Y)=25andn(XUY)=40
We know: n(X∪Y)=n(X)+n(Y)−n(X∩Y) ⇒40=20+25−n(X∩Y) ⇒n(X∩Y)=5 ∵X−Y=X−(X∩Y) ⇒n(X−Y)=n(X)−n(X∩Y) ⇒n(X−Y)=20−5=15