SOLUTION: I have a problem that is not from the textbook. My teacher has assigned the following problem and we are to use applications of the quadratic formula. I don't see how to put the pr

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: I have a problem that is not from the textbook. My teacher has assigned the following problem and we are to use applications of the quadratic formula. I don't see how to put the pr      Log On


   

Question 113411: I have a problem that is not from the textbook. My teacher has assigned the following problem and we are to use applications of the quadratic formula. I don't see how to put the problem into a square in order to use the quadratic formula. Here is the problem:
The rate of a bicyclist is 5mph faster than the rate of a runner. The bicyclist travels 12 miles in the same amount of time that it takes the runner to travel 8 miles. Find the rate of the runner.
This is how far I got:
12/x+5 = 8/x then, 8x - 12x +40 = 0
I would really appreciate any help. Thank you in advance.
Tynk

Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
You're on the right track.
You do not need to use the quadratic formula to solve this linear problem.
That is the correct two equation.
12%2F%28x%2B5%29=8%2Fx
12x=8x%2B40
4x=40
x=10
The runner runs at 10 mph, the bicyclist bikes at 15 mph.