<PRE><B>Question 183983</B>
It takes Mary 30 minuites to walk uphill 1 Km from her home to school, but it takes her only 10 minuites to walk from school to home along the same route. What is her average speed, in Km/hr, for the round trip?
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rate = distance / time

rate = (1km + 1km) /((1/2) hr + (1/6)hr)

= 2km/(8/12) hr

= 2km/(2/3) hr

= 3 km/hr
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Cheers,
Stan H.</PRE>