Question 629178
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Hi,
An urn contains 7 one-dollar bills, 5 five-dollar bills, and 3 ten-dollar bills. 15 bills in ALL
 two bill drawn <u>without replacement</u>
P($5 then $1) = {{{ (5/15)(7/14) = 1/6}}}
P(sum is $15) = P($5 then $10) + P($10 then $5) = {{{(5/15)(3/14) + (3/15)(5/14)}}}
Re: TY, the format on this site doesn't allow for tree diagrams.
However there are 15C2  or 105 ways of chosing 2 cards: (15 ways for each $1)