At the construction site, 75 tons of sand are transported by large and small trucks with a load of 8 tons and 5 tons, and several large trucks and small trucks are used respectively fast

At the construction site, 75 tons of sand are transported by large and small trucks with a load of 8 tons and 5 tons, and several large trucks and small trucks are used respectively fast

This problem can't be solved directly, it can only be listed one by one
When the cart is 9, it is not suitable
When the cart is 8, it is not suitable
When the cart is 7, it is not suitable
When the cart is 6, it is not suitable
When the cart is 5, the trolley is 7
When the cart is 4, it is not suitable
When the cart is 3, it is not suitable
When the cart is 2, it is not suitable
When the cart is 1, it is not suitable
Solid can only be big car 5 cars, car 7 cars

A pile of sand is 135 tons. A 5-ton truck has carried it 18 times. How many tons are left now?

There are 135-18 * 5 = 135-90 = 45 tons left

How many times does it take to transport 1423 tons of sand by an 8-ton truck?

1423 is about 1400. 1400 divided by 8 is 175

It is known that the density of steel is 7.8 × 10 ~ (- 179); kg / M ~ (- 179); it is necessary to transport back 20 cubic meters of steel by car. If each car is limited to 10 tons, how many cars can be sent to transport back at one time

20 * 7.8 = 156 tons
156/10=15.6
Sixteen trucks