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A bag contains 4 balls. Each ball is a single color, and 3 distinct colors are represented in the bag. What is the probability that the first 2 balls selected without replacement are the same color? Express your answer as a common fraction.

 Dec 16, 2018
 #1
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+2

Let's say... 1 red, 1 green, 2 blue.

The new question is... What is the probability of selecting 2 blue balls?

First chance... 1 blue ball has chance 2/4, or 1/2.

Second chance... 1 blue ball has chance 1/3. This is because 1 blue ball is left... and only 3 balls are left.

Multiply these two chances... 1/6 probability.

 Dec 16, 2018
 #2
avatar+98034 
+3

Let's say the the balls are

 

B1  B2  R  G

 

The number of permuted sets created by choosing any 2 of the 4 balls is  12

 

Only  1  of these sets contain 2 blue balls....and they can be permuted in two ways

 

{ B1, B2 } or {B2, B1}

 

So

 

2 / 12   =

 

1/ 6

 

 

cool cool cool

 Dec 16, 2018
 #3
avatar+853 
0

Thank you so much!

 Dec 18, 2018

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