SOLUTION: john and mary leave their house at the same time and drive in opposite directions. john drives at 85 mi/h and travels 35 minutes farther then mary, who drives at 40 mi/h. mary's tr

Algebra ->  Customizable Word Problem Solvers  -> Travel -> SOLUTION: john and mary leave their house at the same time and drive in opposite directions. john drives at 85 mi/h and travels 35 minutes farther then mary, who drives at 40 mi/h. mary's tr      Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


    

Question 1104493: john and mary leave their house at the same time and drive in opposite directions. john drives at 85 mi/h and travels 35 minutes farther then mary, who drives at 40 mi/h. mary's trip takes 15 minutes longer than john's. For what length of time does each of them drive?
Found 2 solutions by ikleyn, greenestamps:
Answer by ikleyn(52915) About Me  (Show Source):
You can put this solution on YOUR website!
.
Please read and re-read your post until you find something strange in it.

Then edit and re-post.



Answer by greenestamps(13216) About Me  (Show Source):
You can put this solution on YOUR website!


Please have the courtesy to check your statement of the problem before submitting it. The tutors here don't want to have to spend time trying to figure out what you really meant.

Obviously John travels 35 MILES farther than Mary -- not 35 minutes farther.

So Mary drives distance x miles at 40mph, and John drives (x+35) miles at 85mph; and the time for John's trip is 15 minutes (1/4 hour) shorter than the time for Mary's:

%28x%2B35%29%2F85+=+x%2F40-1%2F4
%28x%2B35%29%2F85+=+%28x-10%29%2F40
85%28x-10%29+=+40%28x%2B35%29
85x-850+=+40x%2B1400
45x+=+2250
x+=+50

John drives 50+35=85 miles at 85 mph; his trip takes 85/85 = 1 hour.

Mary drives 50 miles at 40 mph;her trip takes 5/4 hours = 1 hour 15 minutes.