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 

So ths 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  of those times when you 
selected a ten first, you will select a one second.

So you will select a one-dollar bill second ths of the ths
of the times when you select a ten first. So the desired probability is

× = 

Edwin