We will define the following variables to solve the problem:
x = amount of round trips from 10 tons truck
y = amount of round trips from 12 tons truck
We write the system of equations:
x + y = 20
10x + 12y = 226
The solution to the system of equations is:
x = 7
y = 13
Answer:
10 tons truck makes 7 round trips
12 tons truck makes 13 round trips