Question
A bag contains 5 red and 4 green discs , three discs are randomly drawn from a bag what is the probability at least 1 is red and the probability at most one is green?
Answers
Damon
find probability that all are green
first one 4/9
second one 3/8
third one 2/7
all green = (4/9)(3/8)(2/7)
answer = 1 - that result
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find probability that 9 of 9 are red
find probability that 8 of 9 are red
that sum
is the probability that zero or one is green
first one 4/9
second one 3/8
third one 2/7
all green = (4/9)(3/8)(2/7)
answer = 1 - that result
=============================
find probability that 9 of 9 are red
find probability that 8 of 9 are red
that sum
is the probability that zero or one is green