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A bag has 7 red balls, 4 yellow balls, and 9 green balls. What is the probability that two balls picked randomly are both the same color?

 Jul 20, 2020
 #1
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There are 7 + 4 + 9 = 20 balls altogether.

 

You can pick two balls of the same color if you:

1)  pick two red balls:  (7/20) x (6/19) = ........

2)  pick two yellow balls:  (4/20) x (3/19) = ......

or

3)  pick two green balls:  (9/20) x (8/19) = ........

 

You'll need to do the three individual calculations and add their answers together ...

 Jul 20, 2020

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