Question 901165
On a four mile hike, you walk the first 2 miles at 3m/hr. How fast will you have to go in order to arrive exactly one hour after you left?
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For first 2 miles:
Travel time=distance/speed=2/3 hr, leaving 1/3 hr to finish 2 miles of hike
speed=distance/travel time
required speed=2/(1/3)=6
How fast will you have to go in order to arrive exactly one hour after you left? 
6 mph