The load ratio of cart to cart is 5: 2, and the ratio is 2.5.

The fuel consumption ratio of cart and cart is 1 1: 5, and the ratio is 2.2.

So it will be more fuel-efficient to use a big car as much as possible.

The maximum number of shopping carts is 13. But there will still be 1 ton left, so we have to call another car. A ton of fuel consumption of a car is equivalent to two meals.

This will consume extra fuel.

It was 12 when pushing the cart. There are three cars, which can be shipped out. This * * * consumption11*12+5 * 3 =147 L.

The check results show that the fuel consumption of this scheme is the lowest.

Therefore, using 12 large trucks and 3 small trucks to transport coal has the least total oil consumption, and at least 147L oil is needed.

You got it? I hope I can help you!