SOLUTION: Michelle drove to a friend's house at a rate of 40mph. She returned by the same route at a rate of 45mph. The driving time for the round trip was 4 hours. What was the distance she

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Question 484014: Michelle drove to a friend's house at a rate of 40mph. She returned by the same route at a rate of 45mph. The driving time for the round trip was 4 hours. What was the distance she traveled?
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
: Michelle drove to a friend's house at a rate of 40mph.
She returned by the same route at a rate of 45mph.
The driving time for the round trip was 4 hours.
What was the distance she traveled?
:
let d = the one-way distance
then
2d = the total distance traveled
:
Write time equation: time = dist/speed
:
to time + return time = 4 hrs
d%2F40 + d%2F45 = 4
multiply by 360
360*d%2F40 + 360*d%2F45 = 4(360)
Cancel the denominators, results:
9d + 8d = 1440
17d = 1440
d = 1440%2F17
d = 84.7
therefore
2 * 84.7 = 169.4 total distance traveled