Give the step-by-step reasoning process and then the final answer. Venus is at the deli to get subs for a party. She needs 81 inches of sub. The shop sells 5 and 8 inch subs. If she buys two 8 inch subs, how many 5 inch subs does she need to buy?
The two 8 inch subs total 16 inches because 2 x 8 = 16. She still needs 65 inches of sub because 81 - 16 = 65. She needs to buy 13 five inch subs because 65 / 5 = 13.
The final answer: 13.