There is not one distance where the cost would be the same. The reason is because the price per mile is the same, but the extra charges are different. This means that no matter when the distance is the same, the cost would always be different.
The solution is where the 2 graphs intersect At A and B. x + y + 2 = 0 transforms to y = -x - 2 which has slope -1 and y-intercept of -2 as in Graph C.
