Two dump trucks have capacities of 10 tons and 12 tons. they make a total of 20 round trips to haul 226 tons of topsoil to be used to landscape a new development. how many round trips did each truck make?

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
 
 10 tons truck makes 7 round trips
 12 tons truck makes 13 round trips

1. 0.3 •4 is the same as 4 groups of 0.32. 7•0.8 is the same as 7 groups of 0.83. it increases by 0.5 every time, so 0.5x4 it increases by 0.9 every time, so 0.9x5. 0.9•12=10.86. 0.47•5=2.35i can finish the next ones in a separate post