Xiangyang primary school organizes fifth-grade students to go on an autumn outing. Can you solve the math problem of autumn outing? A total of 156 fifth-grade teachers and students went for an autumn outing. How to save money by renting a car? (1) fully rented shopping cart: 156÷42=3 (cars) ... 30 people,

* * * Need 1000×4=4000 yuan;

(2) Rent 3 carts, 156-42×3=30 people,

Rent a car: 30÷24= 1 (car) ... 6 people,

* * * Need1000× 3+600× 2 = 4,200 yuan;

(3) Rent 2 trolleys:

We also need to rent three cars: (156-42×2)÷24=3 (cars),

* * * Need1000× 2+600× 3 = 3,800 yuan;

(4) Rent 1 shopping cart:

Then we have to rent five cars: (156-42)÷24=4 (cars) ... 18 people,

* * * Need1000+600× 5 = 4,000 yuan;

Answer: From the above calculation, we can rent two buses and three cars to save money.