Answer:
11
Explanation:
Subtract 27 by 12 to figure out how many rode in canoes. Then divide by 3 for each canoe which means that there are 4 canoes. On return trip, there are 16 people riding in canoes because there are 4 per canoe, which means that 27 people in total - 16 people in canoes is 11 people riding the motorboat on the way back.