Thank you for the opportunity to help you with your question!
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
P (not more than 2 red balls) = P (one red and 4 other) or P (two red and 3 other)
= 1/100 + 3/200
Please let me know if you need any clarification. I'm always happy to answer your questions.
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.
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