1. There are five $5 and three $10 bills in a bag. A person reaches in and pulls out two bills. What is the probability of the sum of the bills will be $10, $15 or $20?

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MrPatel
Mar 31, 2017

#1**+2 **

Hello Mr Patel :)

1. There are five $5 and three $10 bills in a bag. A person reaches in and pulls out two bills. What is the probability of the sum of the bills will be $10, $15 or $20?

5,5,5,5,5, 10,10,10 8 notes altogether.

$10=$5+$5

\(P(5,5)= \frac{5}{\not{8}^2}\times \frac{\not{4}^1}{7}=\frac{5}{14}\)

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$15 = $5+$10 or $10+$5

\(P(5,10)= \frac{5}{8}\times \frac{3}{7}=\frac{15}{56}\\ P(10,5)= \frac{3}{8}\times \frac{5}{7}=\frac{15}{56}\\ \text{P(sum of 15)}=\frac{30}{56}=\frac{15}{28} \)

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You can do the $20 yourself I think :)

Melody
Mar 31, 2017