Posted by **Molly** on Monday, November 15, 2010 at 10:05pm.

Four balls are simultaneously picked at random from a jar containing 2 red balls, 2 green balls, and 6 yellow balls.

What is the probability that exactly two of the selected balls will be red?

- Math -
**Reiny**, Monday, November 15, 2010 at 10:14pm
Using combination symbols,

prob = C(2,2)/C(10,2) = 1/45

or

prob = (2/10)(1/9) = 2/90 = 1/45

- Math -
**Anonymous**, Monday, December 3, 2012 at 8:45pm
it just says how many red balls are there

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