Well, first, find-out how fast he was going the first time, by dividing 310 by 5. This gives you 62 mph. Now, divide 403 miles by 62 miles per hour in order to find-out how long it would take him to drive 403 miles, if he is constantly doing 62 mph. Your final answer is six-and-a-half hours.
To solve for c, you need to get c onto one side of the equation, or make it c=__. So what I would do first is subtract a/b from both sides
a/b + c = d/c
-a/b
a/b - a/b + c = d/c - a/b
c = d/c-a/b
Check the picture below.
notice, the focus point is at 4,5 whilst the directrix line is at y = -3, below the focus point, meaning the parabola is vertical and opening upwards.
keeping in mind that the vertex is "p" distance from either of these fellows, then the vertex is half-way between both of them, notice in the picture, the distance from y = 5 to y = -3 is 8 units, half that is 4 units, thus the vertex 4 units from the focus or 4 units from the directrix, that puts it at (4,1), whilst "p" is 4, since the parabola is opening upwards, is a positive 4 then.

answer is 31
Step-by-step explanation: