Mathematics problems of seventh grade in People's Education Press

Solution: (1) If you want to buy x cars, you need to buy (10-x) vans.

7x+4( 10-x)≤55，

The solution is x≤5.

And because x≥3, then x = 3, 4 or 5.

Therefore, there are three car purchase schemes:

Option 1: 3 cars and 7 vans;

Option 2: 4 cars and 6 vans;

Option 3: 5 cars and 5 vans.

(2) The daily rent for Option 1 is:

3× 200+7×110 =1370 (yuan);

The daily rent for option 2 is:

4× 200+6×110 =1460 (yuan);

The daily rent for Option 3 is:

5× 200+5×110 =1550 (yuan).

Therefore, in order to ensure that the daily rent is not lower than 1500 yuan, the third option should be selected.