SOLUTION: The Browns are moving across the country. Mr. Brown leaves 3.5 hours before Mrs. Brown. If he averages 60mph and she averages 80mph, how many hours will it take Mrs. Brown to cat

Algebra ->  Finance -> SOLUTION: The Browns are moving across the country. Mr. Brown leaves 3.5 hours before Mrs. Brown. If he averages 60mph and she averages 80mph, how many hours will it take Mrs. Brown to cat      Log On


   

Question 1153887: The Browns are moving across the country. Mr. Brown leaves 3.5 hours before Mrs. Brown. If he averages 60mph and she averages 80mph, how many hours will it take Mrs. Brown to catch up to Mr. Brown?

Found 2 solutions by josgarithmetic, ikleyn:
Answer by josgarithmetic(39617) About Me  (Show Source):
Answer by ikleyn(52781) About Me  (Show Source):
You can put this solution on YOUR website!
.

This problem deserves to be solved in one line, to impress you


    time to catch up = %283.5%2A60%29%2F%2880-60%29 = 210%2F20 = 10.5 hours = 10 hours and 30 minutes.    (1)



EXPLANATION    (in case if you need it . . . )


    The numerator  3.5*60 = 210 miles is the head start.

    The denominator (80-60) = 20 mph is the difference of their speeds, same as the rate of approaching.


    The formula (1) is the form of the standard formula  time = distance%2Frate  adapted for this problem.

    Here the distance is the value of the head-start and rate is the rate of approaching.

Solved (!)  And explained (!)  And completed (!)  And in one line (!)

-------------------

See introductory lessons on Travel and Distance problems
    - Travel and Distance problems
    - Travel and Distance problems for two bodies moving in opposite directions
    - Travel and Distance problems for two bodies moving in the same direction (catching up)
in this site.

They are written specially for you.

You will find the solutions of many similar problems there.

Read them and learn once and for all from these lessons on how to solve simple Travel and Distance problems.

Become an expert in this area.


/\/\/\/\/\/\/\/

The person, who really understands such problems, ALWAYS solves them in one line (or even MENTALLY . . . )