John has 13 ten-dollar bills, 11 five-dollar bills, and 17 one-dollar bills. If John needs to pay exactly $128, what is the least number of bills he will need to use?  Answers
A) 14 B) 16 C) 17 D) 19 E) 20
Any combination of ten-dollar and five-dollar bills cannot add up to amount ending with 8. John has to use at least 3 one-dollar bills. To gather the rest, $125, John needs to use a minimum of 13 bills: 12 ten-dollar bills and 1 five-dollar bill.   Answer: 16
<result>B</result>
John has 13 ten-dollar bills, 11 five-dollar bills, and 17 one-dollar bills. If John needs to pay exactly $128, what is the least number of bills he will need to use?