SOLUTION: Rajee drove from Newark, NJ, to New Brunswick during rush hour at an average speed of 30 miles per hour, and then drove back the same way at an average speed of 60 miles per hour.

Algebra ->  Average -> SOLUTION: Rajee drove from Newark, NJ, to New Brunswick during rush hour at an average speed of 30 miles per hour, and then drove back the same way at an average speed of 60 miles per hour.       Log On


   

Question 1145371: Rajee drove from Newark, NJ, to New Brunswick during rush hour at an average speed of 30 miles per hour, and then drove back the same way at an average speed of 60 miles per hour. If the round trip took 1 hour and 15 minutes, how many miles is Rajee's one-way trip from New Brunswick to Newark, NJ?
Answer by ikleyn(52803) About Me  (Show Source):
You can put this solution on YOUR website!
.
Let "d" be one way distance under the question.


Then  d%2F30  is the driving time in one direction, in hours, while

      d%2F60  is the driving time in other direction.


The total "time" equation is  


    d%2F30 + d%2F60 = 5%2F4   hours.


To solve it, multiply both sides by 60.  You will get


    2d   +  d = 75

    3d        = 75

     d        = 25 miles.      ANSWER


CHECK.   25%2F30 + 25%2F60 = 50%2F60 + 25%2F60 = 75%2F60 = 5%2F4 hours.   ! Correct !

Solved.

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

Using  "time"  equation is the  STANDARD  method of solving such problems.

It is simple,  logical,  straightforward,  economic and robust  (works in standard way for any input data).

Going in this way,  you will never make a mistake - the logic of the method
prevents you of making mistakes.

From this lesson,  learn on how to write,  how to use and how to solve a  "time"  equation.

To see many other similar solved problems,  look into the lessons
    - Had a car move faster it would arrive sooner
    - How far do you live from school?
    - Earthquake waves
    - Time equation: HOW TO use, HOW TO write and HOW TO solve it
in this site.