conversations.from: human
conversations.value: I would love to understand how to solve this problem: It costs $.10 to print one page. Jenny wants to print 7 copies of her 25-page essay. She also wants to buy 7 pens that each cost $1.50. If she pays the store with 2 twenty dollar bills, how much money should she get in change?
  Can you explain?
conversations.from: assistant
conversations.value: Jenny needs to print 7*25= 175 pages.
  This will cost 175*$.10 =$17.5.
  The pens will cost 7*$1.50=$10.50.
  In total, she will spend $17.5+$10.5=$28.
  Since she pays with 2 twenty dollar bills she pays with 2*20=40 dollars.
  Thus, she will get $40-$28=$12 in change.