Posted by **MIA** on Wednesday, July 24, 2013 at 12:34am.

From a group of 12 people, you randomly select 3 of them. Find the probability that at least one of them is among the 3 oldest people in the group

- STATISTICS -
**Chol**, Wednesday, July 24, 2013 at 12:56am
There are 12C3 = 220 ways, group of 3 people from 12

There are 9C3 = 84 ways, none of the three oldest.

220-84 = 136 groups where at least one member is 3 oldest.

136/220 = 0..618

- STATISTICS -
**Graham**, Wednesday, July 24, 2013 at 4:32am
Alternatively: It's the complement of the probability that none of them is among that group.

Let E[n] be the indexed event that the [n]th person selected is not one of the three oldest.

1 - P(E1) P(E2|E1) P(E3|E1 and E2)

= 1 - (9/12) (8/11) (7/10)

= 0.61818....

## Answer This Question

## Related Questions

- STATISTICS - From a group of 12 people, you randomly select 3 of them. Find the ...
- statistics - Data shows that 88% of the people in a certain population are right...
- statistics - Suppose that in a large population the proportion of people that ...
- math - Find the probability of at least one birthday match among a group of 48 ...
- math - 2) In a certain instant lottery game, the chances of a win stated as "3 ...
- Statistics - 4 people are chosen at random from a group of 15 people. What are ...
- Statistics - The father of a junior high school student wants to determine the ...
- Statistics - The father of a junior high school student wants to determine the ...
- statistics - a sample of 120 men and women randomly divided into 3 groups with ...
- Math- Prob Stat - The probability that a student in this school has a job is 65...

More Related Questions