15. (10 points) The number of students from Primary School 1 and Primary School 2 on a spring outing is a multiple of 10. If both schools rent 14-seat tourist buses, then they need to rent a total of 72 such buses; if they rent 19-seat tourist buses, then Primary School 2 needs to rent 7 more such buses than Primary School 1. It is known that students from the two schools do not share buses, and each bus is filled as much as possible. Question: How many students from each school are participating in this spring outing?
【Answer】Solution: $72 \times 14=1008$ (people), estimate the total number of people from both schools to be 1000 or 990;
Assuming the total number of people from both schools is 1000, $1000 \div 19 \approx 53$ (vehicles);
Assuming the total number of people from both schools is 990, $990 \div 19 \approx 53$ (vehicles),
both require 53 19-seat tour buses, and because the second school needs to rent 7 more of these buses than the first school, the number of buses must be odd;
The first school rents these buses: $(53-7) \div 2=23$ (vehicles), $23 \times 19=437$ (people);
The second school rents these buses: $23+7=30$ (vehicles), $30 \times 19=570$ (people),
Based on the known conditions, and using 14-seat tour buses, 72 vehicles are needed for verification, further confirming that the first school has 430 people, and the second school has 570 people.

Answer: The first school has 430 people participating in this spring outing, and the second school has 570 people participating in this spring outing.