<PRE><B>Question 174973</B>
A car travelled 470 km from Sudbury to Brandford in 5 hours. For part of the trip, the car traveled at 100 km/h. For the rest of the trip it traveled at 90 km/h. How far did the car travel at each speed? 
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100 kph section DATA:
Distance = x km ; rate = 100 kph ; time = d/r = x/100 hrs.
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90 kph section DATA:
Distance = 470 - x km ; rate = 90 kph ; time = d/r = (470-x)/90 hrs
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EQUATION:
time + time = 5 hrs
x/100 + (470-x)/90 = 5
90x + 100(470-x) = 450*100
90x + 100*470 - 100x = 450*100
-10x = -20*100
x = 200 km (distance traveled at 100 kph)
470-x = 270 km (distance traveled at 90 kph)
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Cheers,
Stan H.
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