<PRE><B>Question 209164</B>
A subway train makes six stops of equal length during its 21 km run. The train is actually moving for 20 min of the trip. At most how long can the train remain at each station if the average speed for the trip, including stops is to be at least 36 km/h? show work.
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rate = 21 km /20 min = 1.05 km/min (rate while the train is moving)
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36 km/hr = 36 km/(60 min) = 0.6 km/min (minimum overall rate for the trip)
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time required at 0.6 km/min = (21 km)/(0.6 km/min)= 35 minutes
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Amount of time for 6 stops = 35-20 = 15 minutes
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Average stopping time at each station: 15min/6 = 2.5 minutes
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Cheers,
Stan H.
Reply to stanbon@comcast.net or algebra.com
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