Question

in a hostel there are 125 students, out of which 80 drink tea, 60 drink coffee and 20 drink tea and coffee both. Find the number of students who do not drink tea or coffee

Answer 1

See the attach file hope it will be helpful

Answer 2

Given:

In hostel

Total number of students =125

Number of students who drink tea=80

Number of students who drink coffee=60

Number of students who drink tea and coffee=20

To find:

Number of students who do not drink tea or coffee.

Solution:

Let

A=Tea

B=Coffee

n(A)=80

n(B)=60

U=125

$n(A\cap B)=20$

We know that

$n(A\cup B)=n(A)+n(B)-n(A\cap B)$

Using the formula

$n(A\cup B)=80+60-20=120$

$n(A\cup B)'=U-n(A\cup B)=125-120=5$

Hence, the number of students who do not drink tea or coffee=5