The mass of coal in one railway carriage is 60 tons. How many trips do you need to make on a dump

The mass of coal in one railway carriage is 60 tons. How many trips do you need to make on a dump truck with a carrying capacity of 20 tons to unload 3 such cars with coal?

Brief notation of the condition:

in 1 carriage – 60 tons;

in 3 cars -? t; ? flights;

1 trip – 20 t.

1 solution.

1. Let’s find the total amount of coal in 3 cars:

3 60 = 180 t.

2. Let’s calculate the number of flights:

180: 20 = 9 flights.

2 solution.

1. Let’s calculate the number of trips for unloading 1 wagon;

60: 20 = 3 flights.

2.3 wagons:

3 3 = 9 flights.

Answer: a dump truck needs to make 9 trips.