conversations.from: human
conversations.value: I'm completely lost with this math problem: Whitney’s mom gave her two $20 bills to spend at the school book fair. Whitney has decided to buy 2 posters, 3 notebooks, and 2 bookmarks. Each poster costs $5, each notebook costs $4, and each bookmark costs $2. How much money, in dollars, will Whitney have left over after the purchase?
  Can you give me a hand?
conversations.from: assistant
conversations.value: Whitney is buying 2 posters for $5 each, so the posters will cost 2*$5= $10 total cost for posters.
  Whitney is buying 3 notebooks for $4 each, so the notebooks will cost 3*$4= $12 total cost for notebooks.
  Whitney is buying 2 notebooks for $2, so the bookmarks 2*$2= $4 total cost for bookmarks.
  Since Whitney is paying $10 for posters, $12 for notebooks, and $4 for bookmarks, her total purchase will cost $10+$12+$4= $26 total purchase cost.
  Whitney’s mom gave her 2 $20 bills, so she will be paying with 2*$20=$40 total payment.
  Since Whitney is paying with $40 and her purchase cost will be $26, she will have $40-$26= $14 left over after the purchase.