1. Rent 5 buses, with freight =250*5= 1250 yuan.
2. Rent 7 buses, and the freight is =200*7= 1400 yuan.
3. Rent 2 buses and 4 buses, and the freight is = 250 * 2+200 * 4 = 500+800 =1300 yuan.
2) Can you design a scheme with the least total freight?
In order to minimize the total freight volume, it is necessary to rent as many buses as possible and make every car as full as possible!
We should rent a No.4 bus, 1 bus.
The lowest freight = 250 * 4+200 *1=1000+200 =1200 yuan.