Question 252110: When Elizabeth visits her friend Andrew, she must first walk uphill, then walk on level ground, then finally walk downhill. She walks home by the same route. She always walks 2km/h when going uphill, 6km/h when going downhill and 3km/h when on level ground. If her total walking time is 6 hours, what is the roundtrip distance she walks?
A 3 2/3 B. 4 km C. 9 km D. 18 km E. 22 km
Answer by hokies(65)   (Show Source):
You can put this solution on YOUR website! E. 22km
For a round trip, she must walk equal amounts of time uphill and downhill, so the non-level ground part of her trip she averages 4 km/hr (average of 2 km/hr and 6 km/hr). The level ground part of her trip she averages 3 km/hr. Therefore, for a 6 hour trip, the distance must be greater than (but not equal to) 18 km and less than (but not equal to) 24 km. The only choice that fits is E. 22 km.
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