<span>Simplifying
x + -1.4 = 7.82
Reorder the terms:
-1.4 + x = 7.82
Solving
-1.4 + x = 7.82
Solving for variable 'x'.
Move all terms containing x to the left, all other terms to the right.
Add '1.4' to each side of the equation.
-1.4 + 1.4 + x = 7.82 + 1.4
Combine like terms: -1.4 + 1.4 = 0.0
0.0 + x = 7.82 + 1.4
x = 7.82 + 1.4
Combine like terms: 7.82 + 1.4 = 9.22
x = 9.22
Simplifying
x = 9.22</span>
Let's say that the speed of the freight train is and the one of the passenger train is .
MPH means every hour the freight train covers miles., which means in 3h it will have covered 3 times as much: mi.
Following the same logic, MPH means every hour the passenger train covers miles, meaning after 3h it will have covered 3 times as much as well: mi.
Now, having expressed those distances and speeds algebraically, we find the difference between the two distances covered after 3h, knowing it will be equal to 240:
Knowing this, we can surely affirm that the freight train is travelling at 40MPH and the passenger train is travelling three times as fast, 120MPH.