SOLUTION: Imogene's car traveled 660 mi averaging a certain speed. If the car had gone 6 mph faster, the trip would have taken 1 hour less. Find the average speed.

Question 1145951: Imogene's car traveled 660 mi averaging a certain speed. If the car had gone 6 mph faster, the trip would have taken 1 hour less. Find the average speed.
Answer by ikleyn(52777) (Show Source): You can put this solution on YOUR website!
.

Let x be the average speed under the question.


Then the travel time for 660 miles distance is   hours.


The hypothetical travel time is    hours.


The difference is 1 hour :


     -  = 1  hour.


It is your basic equation, the "time" equation.


To solve it, multiply both sides by x*(x+6).  You will get


    660*(x+6) - 660x = x*(x+6).


Simplify and solve for x


    660*6 = x^2 + 6x

    x^2 + 6x - 3960 = 0

     =  = .


Only positive root makes sense  x =  = 60.


ANSWER.  The average speed under the question is 60 miles per hour.


CHECK.   = 11 - 10 = 1 hour.  ! Precisely correct

Solved.

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SOLUTION: ​Imogene's car traveled 660 mi averaging a certain speed. If the car had gone 6 mph​ faster, the trip would have taken 1 hour less. Find the average speed.

SOLUTION: Imogene's car traveled 660 mi averaging a certain speed. If the car had gone 6 mph faster, the trip would have taken 1 hour less. Find the average speed.