Question 989700
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The sum of their speeds = 392mi/4hrs = 98mi/hr
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x=speed of slower car; x+6 mi/hr=speed of faster car
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x+x+6 mi/hr=98 mi/hr
2x=92 mi/hr
x=46 mi/hr 
ANSWER 1: The slower car traveled 46 mi/hr
s+6 mi/hr=46mi/hr+6mi/hr=52 mi/hr 
ANSWER 2: The faster car traveled 52 mi/hr.