SOLUTION: Brian drives 117 miles to the city. On the drive back home, his average speed decreases by 6 miles per hour. Write two equations (for time, in hours) to the city and back home

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Question 1003705: Brian drives 117 miles to the city. On the drive back home, his average speed decreases by 6 miles per hour.
Write two equations (for time, in hours) to the city and back home where "r" is the average speed (in miles per hour) when driving to the city.
Thank you so much!
Found 2 solutions by josgarithmetic, stanbon:
Answer by josgarithmetic(39621) About Me  (Show Source):
You can put this solution on YOUR website!
RT=D travel rates rule 

TO CITY      r        ()         117
RETURN      r-6       ()         117


Fill in the time cells.
TO CITY      r        117/r             117
RETURN      r-6       117/(r-6)         117



T%5Bgoing%5D=117%2Fr
T%5Breturn%5D=117%2F%28r-6%29

Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
Brian drives 117 miles to the city. On the drive back home, his average speed decreases by 6 miles per hour.
Write two equations (for time, in hours) to the city and back home where "r" is the average speed (in miles per hour) when driving to the city.
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To city DATA:
distance = 117 miles ; rate = r mph ; time = d/r = 117/r hrs
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From city DATA:
distance = 117 miles ; rate = r-6 mph ; time = 117/(r-6) hrs
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Equations:
Time to city = 117/r hrs
----
Time from city = 117/(r-6) hrs
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Cheers,
Stan H.
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