Two coins are taken at random from a bank containing 4 dimes, 8 quarters, and 3 nickels. What is the probability that both coins will be quarters?

1 Answer
GM_Phrostbyte
Jun 29, 2017

#8/30# OR #26.bar6%#

Explanation:

There are a total of 15 coins, so there is an 8 in 15 chance of getting one-quarter. This can be expressed as #8/15#.

Now supposed you do get the quarter the first time. Now there are only 7 quarters left in the bank, and only 14 coins that can be possibly picked. The probability now is #7/14# or #1/2#.

Because picking two coins without replacing them are dependant on which ones you choose, you have to multiply the probabilities.

#8/15*1/2=8/30#

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