Huanggang Middle School plans to organize representatives of Miyoshi students and some teachers to visit the provincial museum. The following is a conversation between Mr. Cheng and Mr. Tao of the Political and Educational Office about car rental: Mr. Cheng: &”;Ping An Passenger Transport Company has 45 and 30 buses available for rent, and the daily rent is

(1) From the meaning of the question, get y=30x 15, y = 45 (x-1); (2) From the meaning of the question, we get 30x 15=45x-45, and the solution is: x=4, so there are 30×4 15=135 teachers and students going out to visit. (3) From the meaning of the question, we get 30a 45b=135, b = 92a3. ∵ A ≥ 1 is an integer, and b≥1 is an integer. B=53 (give up), when a=3, B = 1. ∴ There are two car rental schemes. Three cars for 30 seats, one car for 45 seats, zero cars for 30 seats and three cars for 45 seats. (4) From the meaning of the question, get W=220a 300b, = 220A 300× 990