##### Probability question

label Statistics
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Four balls with different colors: red, yellow, green, and blue, are placed in a box. Every time Amy picks up a ball, then puts it back to the box and draws one again, repeating it five times. What is the probability that she gets at least four red balls in the five draws? What is the probability that she will get no more than two red balls in the five draws?

Oct 26th, 2015

P (at least four red balls) = P(4 red and 1 other) or P( 5 red)

=  (4/20)* 1/20 + 5/20

= 1/100 + 1/4

=  13/50

P (not more than 2 red balls)  = P (one red and 4 other)  or  P (two red and 3 other)

= 1/100  + 3/200

= 1/40

Oct 26th, 2015

For getting at least four red balls in five draws, the answer key says it is a probability of 0.016.  I'm just not sure how to get that answer.  And for getting no more than 2 red balls in five draws, the answer key says it is 0.9.  Again, I'm not sure how they are getting this answer.

Oct 26th, 2015

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Oct 26th, 2015
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Oct 26th, 2015
Sep 21st, 2017
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