<PRE><B>Question 767539</B>
John drove to a distant city in 9 hours. When he returned, there was less traffic, and the trip took only 7 hours. If he drove 12 mph faster on the return trip, how fast did he drive each way?
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let x=speed of going trip
x+12= speed of return trip
distance=travel time*speed(same for both directions)
9x=7(x+12)
9x=7x+84
2x=84
x=42
x+12=54
speed of going trip=42 mph
speed of return trip=54 mph</PRE>