Question

25% people likes to drink
coffee which is 30 people.
The rest prefers tea . What is
total no. of people who took
part in the survey
60
120
90
30​

Answer 1

Answer:

T = Tea

C = Coffee

n means number

n(T) = 30

n(C) = 20

Universal = 50

n(T U C)' = 6 , T union C complement (people who like to drink neither)

Let n(T Π C) i.e. T intersection C (People who like to drink both) = x

n(T) + n(C) - n(T Π C) + n(T U C)' = 50

30 + 20 - x + 6 = 50

56 - x = 50

- x = 50 - 56

-x = -6

x = 6

Therefore people who like to drink BOTH Tea and Coffee are 6.

People who drink coffee = 20

Thus, People who ONLY drink coffee = 20 - 6 = 14 people

I've attached an image with diagram below for better understanding.

Answer 2

Answer:

25×x/100=30

25x=3000

x=120=total