40x+ 15=48x-25

x=5

40x+15 = 48x-25 = 215 people

If you rent a 40-seat bus, you need 6 empty buses and 25 seats *** 1500 yuan.

To rent a 48-seat bus, you need five empty cars and 25 seats *** 1500 yuan.

If you rent four 48-seat buses, 1 40-seat bus, you can take 232 people *** 1450 yuan.

If you rent three 48-seat buses and two 40-seat buses, you can take 224 people *** 1400 yuan.

If you rent two 48-seat buses and three 40-seat buses, you can take 2 16 people *** 1350 yuan, which is the most economical.