Question

11. A survey was conducted of the T.V. programmes watched by 120 students of
a school hostel, on a particular day. It was revealed that 70 students watched
'Aaj Tak' programme and 56 students watched programme on 'Star News
whereas 24 students watched both the programmes. Find the number of
students who did not watch T.V. on that day.​

Answer 1

Given,

Total students = 120

Aaj Tak watcher = 70

Star News watcher = 56

Watcher of both programmes = 24

For, calculating the number of students who didn't watch T.V that day,we need to calculate the number of watchers who only watched Aaj Tak and Star News.

Now,

The number of students who watched only Aaj Tak = Total Aaj tak watcher - Watchers of both programmes = 70-24 = 46

The number of students who watched only Star News = Total Star News watcher - Watchers of both programmes = 56-24 = 32

So,

The total watchers of T.V = Watchers of Aaj Tak only + Watchers of Star News only + Watchers of both programmes = 46+32+24 =  102

So,

The number of students who didn't watch T.V = 120-102 = 18

Hence,the number of students who didn't watch T.V is 18.