Question 1203527
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A truck can be rented from Company A for ​$80 a day plus ​$0.40 per mile. 
Company B charges ​$50 a day plus ​$0.90 per mile to rent the same truck. 
Find the number of miles in a day at which the rental costs for Company A and Company B are the same.
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Use this equation

    80 + 0.40*m = 50 + 0.90*m,


where "m" denotes miles.


The origin of this equation is so clear that I will not spend your time for explanations.

Its left and right sides speak for themselves.


From the equation,

    m = {{{(80-50)/(0.9-0.4)}}} = 60.


<U>ANSWER</U>.  60 miles.


<U>CHECK</U>.  80 + 0.40*60 = 104 dollars = 50 + 0.9*60.    ! correct !
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Solved.