Answer:
The maximum number of people who can sail is 16.
Step-by-step explanation:
Tia has $ 400 to pay the boat rent. The boat rental fee is $ 150. Soon after paying the rent Tia would have a sum of money equal to $ 250 (400-150 = 250).
With the $ 250 remaining Tia will have to pay the additional for each guest. Each guest will cost aunt $ 15. To know how many guests Tia can invite you only need to divide 250 by 15. The result will be 16.6.
So Tia could invite 16 people.