Question

# In a survey of 200 students from 7 different schools, 50 people do not play NFS, 40 people do not play Dota and 10 people do not play any online game. Find the number of people who do not play both the games.

A

80

Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
B

70

No worries! We‘ve got your back. Try BYJU‘S free classes today!
C

60

No worries! We‘ve got your back. Try BYJU‘S free classes today!
D

50

No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution

## The correct option is A 80 Let the number of people who do not play NFS be n(N') = 50. (Given) Similarly, the number of people who do not play Dota be n(D') = 40. (Given) And, the number of people who do not play any game be n((N ∪ D)')=n(N' ∩ D') = 10. (Given) (de-Morgan's law) We have to find the number of people who do not play both the games = n(N∩ D)'. We know from de-Morgan's law that for sets A and B, (A∩B)′=A′∪B′. So, n((N∩D)′)=n(N′∪D′) =n(N′)+n(D′)−n(N′∩D′) =50+40−10 =80

Suggest Corrections
1
Related Videos
de-Morgan's Law
MATHEMATICS
Watch in App
Explore more