(2) Scheme ①: The cost of renting 8 cars with 36 seats: 8,400 = 3,200 yuan,

Option 2: Rent a 7-seater 42-seater car: RMB.

Option 3: Because,

Total cost of renting 6 cars with 42 seats and 1 car with 36 seats: RMB.

Therefore, Scheme ③:42 seats with 6 vehicles, 36 seats 1 vehicle, the most economical ....................... score 8 points.

(Note: As long as Scheme ③ is given, you can get full score of 2 points.)

This is the reference answer.