<PRE><B>Question 204043</B>
On a 100-mile trip,a family drove for 1 hour at 50 mph and then the rest at 60 mph. What was the average speed of the trip?
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Average speed = (total distance)/(total time)
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1 hr at 50 mph = 50 miles
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That leaves 50 miles to go at 60 mph.
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time = d/r = 50/60 = 5/6 hr 
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Equation:
Average speed = 100 miles/ (1hr + 5/6 hr) = 100/(11/6) = 600/11 = 54.5455 mph
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Cheers,
Stan H.</PRE>