Question 685863
Two cars leave towns 640 kilometers apart at the same time and travel toward each other. One car's rate is 10 kilometers per hour more than the other's. If they meet in 4 hours, what is the rate of the faster car? 
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Slower car DATA:
time = 4 hrs ; rate = x kmh  ; distance = 4x km
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Faster car DATA:
time = 4 hrs ; rate = x+10 kmh ; distance = 4x+40 km
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Equation:
distance + distance = 640 km
4x + 4x+40 = 640
8x = 600
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x = 75 kmh (slower car rate)
x+10 = 85 kmh (faster car rate)
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Cheers,
Stan H.