Posted by **James** on Monday, July 11, 2011 at 8:26pm.

There are 5 red and 4 black balls in a box. If three balls are picked without replacement, what is the probability that at least one of them is red?

- MATH -
**Max**, Monday, July 11, 2011 at 8:32pm
First, let's consider the probability that none of the balls are red, or all of them are blue. There are 9 balls, 4 of which are blue. So the chance that 3 blue balls will be chosen is 4/9 * 3/8 * 2/7, or 1/21. You can do the rest from here.

## Answer this Question

## Related Questions

- Math - A bag contains three black balls, four white balls and five red balls. ...
- math - A box contains 8 blue balls and 2 red balls. Three balls are selected ...
- Probability again - A box contains 6 red balls, 4 blue balls, and 2 green balls...
- stats - A box contains 10 red balls and 20 blue balls. Three balls are selected ...
- maths-probability - A box contains n balls of which 2 are red and the rest are ...
- probability - A box contains n balls of which 2 are red and the rest are green...
- Math - A bag contains 6 black balls,5 red balls and 4 white balls,if 3 are ...
- Math - A bag contains 6 black balls,5 red balls and 4 white balls,if 3 are ...
- Probability - A box contains 10 balls. Three of them are white, five are red, ...
- statistics - Suppose a box has eight differently colored tennis balls in it. The...