Five red cards and four blue cards are blaced in a bag, five cards are selected blind from the bag, what is the probablity that they are all red?
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It is a good practice to show whatever work you have done so far, so people know how to help – GaussTheBauss Dec 29 '15 at 03:11
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Possible ways to choose $5$ marbles out $5+4=9$ marbles $$\dbinom{5+4}{5}=\frac{9!}{5!4!}=126$$ Favorable ways?: only $1$. So, the probability is equal to $\frac{1}{126}$.
Jimmy R.
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$\frac{5}{5+4}\times\frac{4}{4+4}\times\frac{3}{3+4}\times\frac{2}{2+4}\times\frac{1}{1+4}=\frac{1}{126}$
