Explain simply why 12 is the correct answer to: 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?. Explanation:
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.