SOLUTION: John took a drive to town at an average rate of 40 mph. In the evening, he drove back at 30 mph. If he spent a total of 7 hours traveling, what is the distance traveled by John?

Algebra ->  Customizable Word Problem Solvers  -> Travel -> SOLUTION: John took a drive to town at an average rate of 40 mph. In the evening, he drove back at 30 mph. If he spent a total of 7 hours traveling, what is the distance traveled by John?      Log On

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Question 1156011: John took a drive to town at an average rate of 40 mph. In the evening, he drove back at 30
mph. If he spent a total of 7 hours traveling, what is the distance traveled by John?

Found 2 solutions by ikleyn, josgarithmetic:
Answer by ikleyn(52803) About Me  (Show Source):
You can put this solution on YOUR website!
.

Let "d" be one-way distance.


He spent  d%2F40  hours driving "to there".


He spent  d%2F30  hours driving back.


The total time is 7 hours:

    d%2F40 + d%2F30 = 7  hours.


You get your basic equation. It is called the "time" equation.


To solve it, multiply both sides by 120.  You will get

    3d + 4d = 7*120

    7d      = 7*120

     d      = 120  kilometers.


ANSWER.  One way distance is 120 kilometers.  Total (two-ways) distance is 240 km.


CHECK.  120%2F40 + 120%2F30 = 3 + 4 = 7 hours.   ! Precisely correct !

SOLVED.

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


Answer by josgarithmetic(39620) About Me  (Show Source):
You can put this solution on YOUR website!
For distance each way d,
total time was d%2F40%2Bd%2F30=7.
Solve.