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avatar+15 

After weeks of being a guest, I became a user! This is the problem:

 

I have 5 red plates and 4 blue plates. If I randomly select two plates to serve dinner on, what is the probability that they're both the same color?

 

I thought the answer was 28 2/5, but that was wrong. I only have one chance left. Thanks in advance!

 Feb 23, 2019
 #1
avatar+15 
-1

Just bumping, this problem is time sensitive.

 Feb 23, 2019
 #2
avatar+5782 
+1

don't bump please, someone will get to it and bumping doesn't help.

 

How can a probability be 28 2/5 ?

 

0 <= Pr[anything] <= 1

 

\(P[\text{both same color}] = \\ P[\text{2 red}]+P[\text{2 blue}] = \\ \dfrac{5}{9}\dfrac{4}{8} + \dfrac{4}{9}\dfrac{3}{8} = \\ \dfrac{20 + 12}{72} = \\ \dfrac{4}{9}\)

.
 Feb 23, 2019

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