SOLUTION: The cross-country team left school and trotted to the duck pond at 3 mph. Then they ran back to the school at 7 mph. If the total trip took 10 hours, how far was it to the duck pon

Algebra ->  Customizable Word Problem Solvers  -> Travel -> SOLUTION: The cross-country team left school and trotted to the duck pond at 3 mph. Then they ran back to the school at 7 mph. If the total trip took 10 hours, how far was it to the duck pon      Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


    

Question 1202570: The cross-country team left school and trotted to the duck pond at 3 mph. Then they ran back to the school at 7 mph. If the total trip took 10 hours, how far was it to the duck pond?
Answer by ikleyn(52858) About Me  (Show Source):
You can put this solution on YOUR website!
.

Write the time equation


    d%2F3 + d%2F7 = 10 hours.


Here d is one way distance, and the terms in the left side 
represent time to the pond and back, respectively.


To solve equation, multiply both sides by 3*7.  You will get

    7d + 3d = 10*3*7

      10d   = 10*3*7

        d   =  3*7 = 21.


ANSWER.  The one-way distance is 21 miles.


CHECK.  Time to get pond is  21%2F3 = 7 hours.

        Time to return back is  21%2F7 = 3 hours.

        Total time is  7 + 3 = 10 hours.   ! correct !

Solved.