# Find Number of People

If there are some people, out of which 40% drink coffee, 40% drink tea, 50% drink milk, 10% drink all the three, 20% drink both coffee and tea, 20% drink both tea and milk, 20% drink both milk and coffee?

### Editorial / Best Answer

hydsarema

• Member Since Aug-2008 | Nov 25th, 2008

t=tea
c=coffee
m=milk
n=number of persons

n(c  or t or m)=n(c) +n(t) +n(m)-n(c &t)-n(t & m)- n(m & c) +n(c & t & m)

40+40+50-20-20-20+10=80

number of persons=80

Showing Answers 1 - 7 of 7 Answers

#### hydsarema Profile Answers by hydsarema

• Nov 25th, 2008

t=tea
c=coffee
m=milk
n=number of persons

n(c  or t or m)=n(c) +n(t) +n(m)-n(c &t)-n(t & m)- n(m & c) +n(c & t & m)

40+40+50-20-20-20+10=80

number of persons=80

#### sneha36 Profile Answers by sneha36

• Aug 29th, 2010

t=tea
c=coffee
m=milk
n=number of persons

n(c  or t or m)=n(c) +n(t) +n(m)-n(c &t)-n(t & m)- n(m & c) +n(c & t & m)

40+40+50-20-20-20+10=80

number of persons=80

#### Predhin Profile Answers by Predhin

• Sep 25th, 2010

Let t represents tea
Let c represents coffee
Let m represents milk
Let n represents number of persons

n(c U t U m)=n(c) +n(t) +n(m)-n(c &t)-n(t & m)- n(m & c) +n(c & t & m)

n=40+40+50-20-20-20+10=80

number of persons, n=80

#### sudiptamukherjee Profile Answers by sudiptamukherjee

• Oct 1st, 2010

n(c)=40;
n(t)=40;
n(m)=40;
n(c&t)=20;
n(t&m)=20;
n(m&c)=20;
n(c&t&m)=10
so, n(c or m or t)= n(c)+n(t)+n(m)-n(c&t)-n(c&m)-n(m&t)+n(c&m&t)
=40+40+50-20-20-20+10
=80

#### praneeta Profile Answers by praneeta

• Oct 15th, 2010

Total number of people=80

#### akarun15 Profile Answers by akarun15

• Nov 26th, 2010

Number of People:80

#### Sen Jacob Profile Answers by Sen Jacob

• Jan 8th, 2011

You can also use Ven diagram for solving this kind of problems.
40%+40%+50%-20%-20%-20%+10% = 80%
So, if there is 100 people, 80 of them are drinking any of these.
How could we tell the exact number of people there?
If there is 10 people, 4drink tea, 4drink coffee, 5drink milk, 1drinks all the three. 2drink both coffee and tea, 2 drink both tea and milk, 2 drink both milk and coffee... :)
so I feel any multiple of 8 could be the answer :D
If I'm not wrong, for least case, 8 is the answer ;) (Ans: 8n - where n=1,2,3,...)
Please tell whether this helps you or not :)