Question

 11       12       13       14     A customer buys 17.01 in gas and requests one five dollar [$5] lottery ticket, two one dollar [$1] lottery tickets, and one [$3] lottery ticket. He gives you two winning tickets to be redeemed: one for ($5) and the other for ($2). How much change would he receive from a $100 bill?*

Answer 1

The customer gave me:
-- a ticket worth  $5
-- a ticket worth  $2
-- a bill worth      $100
     Total. . . . . . .$107

I gave him:
-- some gas worth  $17.01
-- a ticket worth       $  5
-- two $1 tickets      $  2
-- a ticket worth       $  3
        Total. . . . . . . .$27.01

The total value of everything we trade has to be equal.

I owe him    ( $107.00  -  $27.01 )  =   $79.99 in change