SOLUTION: A motorist drives 146km at a certain average speed she then increases the speed by 9km/h and takes the same time to travel the next 164km. find her speeds for both parts of the jou

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Question 1068571: A motorist drives 146km at a certain average speed she then increases the speed by 9km/h and takes the same time to travel the next 164km. find her speeds for both parts of the journey. pls help.
Found 3 solutions by ankor@dixie-net.com, stanbon, MathTherapy:
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
A motorist drives 146km at a certain average speed she then increases the speed by 9km/h and takes the same time to travel the next 164km.
find her speeds for both parts of the journey.
:
let s = his original speed
then
(s+9) = the increased speed
:
Write a time equation; time = dist/speed
146%2Fs = 164%2F%28%28s%2B9%29%29
cross multiply
164s = 146(s+9)
164s = 146s + 1314
164s - 146s = 1314
18s = 1314
s = 1314/18
s = 73 km/h is his original speed
:
You can find the faster speed, the check the times with these solutions, should be equal

Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
A motorist drives 146km at a certain average speed she then increases the speed by 9km/h and takes the same time to travel the next 164km. find her speeds for both parts of the journey. pls help.
-------------------
Slower speed DATA:
dist = 146 km ; rate = r km/hr ; time = d/r = 146/r hr
------------
Faster speed DATA:
dist = 164 km ; rate r+9 km/hr ; time = 164/(r+9) = hr
------------
Equation:
time = time
146/r = 164/(r+9)
-----
146r + 146*9 = 164r
--------
18r = 146/9
r = 0.90 km/hr (slower rate)
r+9 = 9.9 km/hr (faster rate)
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Cheers,
Stan H.
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Answer by MathTherapy(10552) About Me  (Show Source):
You can put this solution on YOUR website!
A motorist drives 146km at a certain average speed she then increases the speed by 9km/h and takes the same time to travel the next 164km. find her speeds for both parts of the journey. pls help.