SOLUTION: You have three $1 bills, four $5, and two $10 bills in your wallet. You select a bill at random. Without replacing the bill, you choose a second bill at random.Find p($10 then $1)

Algebra ->  Probability-and-statistics -> SOLUTION: You have three $1 bills, four $5, and two $10 bills in your wallet. You select a bill at random. Without replacing the bill, you choose a second bill at random.Find p($10 then $1)      Log On


   



Question 112267: You have three $1 bills, four $5, and two $10 bills in your wallet. You select a bill at random. Without replacing the bill, you choose a second bill at random.Find p($10 then $1)
Answer by Edwin McCravy(20056) About Me  (Show Source):
You can put this solution on YOUR website!
 
You have three $1 bills, four $5, and two $10 bills in your wallet. You 
select a bill at random. Without replacing the bill, you choose a second bill 
at random.  Find p($10 then $1)

There are 9 bills, 2 of which are tens, so the probability of choosing
a ten first is 2%2F9

So 2%2F9ths of the times you try you will select a ten first.

If you select a ten first and don't replace it, there are 8 bills left to
select second, 3 of which are ones. So 3%2F8 of those times when you 
selected a ten first, you will select a one second.

So you will select a one-dollar bill second 3%2F8ths of the 2%2F9ths
of the times when you select a ten first. So the desired probability is

2%2F9×3%2F8 = 1%2F12

Edwin