Therefore, the fare of a flight is 22 yuan.

The coach fare is 25 yuan.

There are x people in a class.

Class 2 =102-x.

X*22+( 102-X)25=2388

22x+2550-25x=2388

3x= 162

x=54

There are 54 students in Class One and 48 students in Class Two.

102*20=2040

2388-2040=348 yuan

Save 348 yuan

48*25= 1200 yuan

If you buy three more tickets

51* 22 =1122 yuan

Buy 5 1.