how many hours before they are at the same distance

Question

Two trucks are driving on the same highway at the same time. Truck 1 is 10 miles from Smithtown. Its distance from Smithtown, in miles, after x hours can be found using the expression 10 + 55x. The distance of Truck 2 from Smithtown is represented by the graph below. Exactly how many hours will pass before the two trucks are each the same distance from Smithtown?

Answer 1

This can't be solved without the graph. However, if you can look at the graph and find the equation of the line, then you can do it. Assuming that the graph is a straight line, (and it most likely is!), then it's easy. Just set the given equation equal to the equation of the line in the graph and solve for x.

If you can't find the equation of the graph's line, find the coordinates of 2 points on that line (x,y)'s and submit another question to find the equation of a line that passes through (x₁, y₁) and (x₂, y₂).

If that second line is 20 + 45x,

10+55x = 20+45x

55x-45x = 20 - 10

10x = 10

x = 1