SOLUTION: David is traveling to airport to catch a flight. if he travels at speed of 30 mph, he is late by 13 minutes. if he travels at speed of 40 mph,he will arrive 7 minutes earlier than

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Question 1150906: David is traveling to airport to catch a flight. if he travels at speed of 30 mph, he is late by 13 minutes. if he travels at speed of 40 mph,he will arrive 7 minutes earlier than the scheduled departure time of the flight. what is the distance to the airport(in miles).
Answer by ikleyn(52814) About Me  (Show Source):
You can put this solution on YOUR website!
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Let "d" be the distance to the airport.


Then the time from home to the destination point at 30 mph is  d%2F30 hours.

     The time from home to the destination point at 40 mph is  d%2F40 hours.



The difference of these times is 13 minutes PLUS 7 minutes, or 20 minutes, which is  1%2F3  of an hour.


It gives you this "time" equation


    d%2F30 - d%2F40 = 1%2F3.


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


    4d - 3d = 40,

     d      = 40.


ANSWER.  The distance to the airport is 40 miles.

Solved.

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Using  "time"  equation is the  STANDARD  method of solving such problems.
From my solution,  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
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    - Time equation: HOW TO use, HOW TO write and HOW TO solve it
in this site.


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