The mass of coal in a railway carriage is 60 tons. A dump truck can take three tenths of this cargo.

The mass of coal in a railway carriage is 60 tons. A dump truck can take three tenths of this cargo. How many trips need to be done on a dump truck to unload 6 such wagons.

1. Find out how many tons of coal a dump truck can pick up at one time. To do this, divide the entire weight of coal by the denominator and multiply by the numerator of the part of the weight of the cargo that the dump truck can pick up at one time:
60 t / 10 * 3 = 18 t.
2. Find out how many tons of coal are in 6 cars. To do this, we multiply the weight of coal in one car by the number of given cars:
60 t * 6 = 360 t.
3. Let’s find out how many trips a dump truck needs to make to pick up all the coal from 6 cars:
360t / 18t = 20 times.
Answer: in order to pick up coal from 6 wagons, a dump truck needs to make 20 trips.