# Math Help - conditionnal probability!

1. ## conditionnal probability!

if five balls are selected randomly from a total of ten balls without replacement. calculate the probability of getting exactly two red balls out of six red balls

pls i need help on the problem, thanks!

2. ## Re: conditionnal probability!

You have 10 balls in total, 6 are red, so 4 are not red.

You want P(R,R,NR,NR,NR) in any order.

So that's (6/10)(5/9)(4/8)(3/7)(2/6) * 4
= 2/21
Could someone confirm please? I might have missed something.

3. ## Re: conditionnal probability!

Originally Posted by lawochekel
if five balls are selected randomly from a total of ten balls without replacement. calculate the probability of getting exactly two red balls out of six red balls
There are six red balls, so there are four others.
Choose two of six and three of four.