# Find out how many people have visited 38 pupil were asked if they are visited Thailand,Brunei or Indonesia before. 4 of them have been to all three counties, 8 have been to Thailand &...

Find out how many people have visited

38 pupil were asked if they are visited Thailand,Brunei or Indonesia before. 4 of them have been to all three counties, 8 have been to Thailand & Bruneu,15 been brunei & Indonesia,& 11 of them been Thailand and Indonesia. Given 18 had been to Thailand, 19 Brunei & 26 Indonesia. Find out,How many people have visited

A) One of the three countries only

B)More than one of the three countries.

jeew-m | Certified Educator

This question is based on sets.

Let;

T = set of pupil who has been to thailand

B = set of pupil who has been to Brunei

I = set of pupil who has been to Indonesia

According to the data

`n(T nn B nn I) = 4`

`n(T nn B) = 8-4 = 4`

`n(T nn I) =11-4 = 7`

`n(I nn B) = 15-4 = 11 `

It is given that;

n(T) = 18

n(B) =19

n(I ) =26

Pupil only have been to Thailand

= `18-n(T nn B)-n(T nn I)-n(T nn B nn I)`

= 18-4-7-4

= 3

Pupil only have been to Brunei

= `19-n(T nn B)-n(B nn I)-n(T nn B nn I)`

= 19-4-11-4

= 0

Pupil only have been to Indonesia

= `26-n(I nn B)-n(T nn I)-n(T nn B nn I)`

= 26-11-7-4

= 4

A)

Number of people that visited one country only = 4+3 = 7

B)

Number of people that visited more than one country

= total people - Number of people visited one country only

= (18+19+26) - 7

= 56