d=rt word problem

JERRY GRAHAM

New member
Joined
Feb 18, 2006
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9
The problem is: Bob and Carol moved to Bainbridge. Carol drove for ten hours for "X" miles per hour. Bob drove a U-Haul. He had to drive 10 miles an hour less than Carol. His trip took 15 hours. How far away did they live from Bainbridge. I must show all work (formula used, etc.) and show that I checked my work. I can't figure out how to work this because I don't think I have enough information. HELP!
 
Hello, Jerry!

Bob and Carol moved to Bainbridge.
Carol drove for ten hours at \(\displaystyle x\) miles per hour.
Bob drove at 10 mph slower than Carol; his trip took 15 hours.
How far away did they live from Bainbridge?
Carol drove for 10 hours at \(\displaystyle x\) mph . . . She drove \(\displaystyle 10x\) miles.

Bob drove for 15 hours at \(\displaystyle x-10\) mph . . . He drove \(\displaystyle 15(x-10)\) miles.

Since they drove the same distance: \(\displaystyle \:10x\:=\:15(x\,-\,10)\)

Solve for \(\displaystyle x\) and we get: \(\displaystyle x\,=\,30\) . . . That's Carol's speed.


Since she drove at that speed for 10 hours, her distance was: \(\displaystyle \,10\,\times30\:=\:300\) miles.

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Check

Bob drove 10 mph slower . . . at 20 mph.
He drove 15 hours at 20 mph . . . His distance was: \(\displaystyle \.15\,\times 20\:=\;300\) miles.
\(\displaystyle \;\;\)Check!
 
That really was a help. I had gotten the formula 10x=15(x-10), and couldn't figure where to go from there. duh. Thanks again.
 
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