$4 \cdot 202$ City A has 157 tons of goods to be transported to City B, large trucks have a load capacity of 5 tons, small trucks have a load capacity of 2 tons, large trucks consume 20 liters of fuel, small trucks consume 10 liters of fuel, how many large trucks and small trucks should be used to minimize fuel consumption?
[Solution] The fuel consumption for transporting goods with a large truck is 4 liters/ton, and for a small truck, it is 5 liters/ton. Therefore, to minimize fuel consumption, we must use the large truck as much as possible. 157 divided by 5 gives a quotient of 31 and a remainder of 2, so we use 31 large trucks and 1 small truck to transport the goods, which results in the least fuel consumption.