SOLUTION: Hillary went on a 120 mile trip to a soccer game. On the way back, due to road construction she had to drive 15 miles per hour slower. This made the trip take 18 hours longer. How

Algebra ->  Customizable Word Problem Solvers  -> Misc -> SOLUTION: Hillary went on a 120 mile trip to a soccer game. On the way back, due to road construction she had to drive 15 miles per hour slower. This made the trip take 18 hours longer. How       Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


    

Question 1005989: Hillary went on a 120 mile trip to a soccer game. On the way back, due to road construction she had to drive 15 miles per hour slower. This made the trip take 18 hours longer. How fast did she drive to the soccer game?
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
Same problem, different numbers.
==========================
A car travels 380 miles averaging a certain speed. If the car had gone 5 mph faster the trip would have take 1 hour less. What was the average speed?
---------------
d = r*t
t = d/r
t = 380/r
t-1 = 380/(r+5)
-----
380/r - 1 = 380/(r+5)
(380 - r)/r = 380/(r+5)
(380 - r)*(r+5) = 380r
(r-380)*(r+5) = -380r
r^2 + 5r - 1900 = 0