Problema Solution

During the first part of a trip, a canoeist travels 70 miles at a certain speed. The canoeist travels 6 miles on the second part of the trip at a speed 5 mph slower. The total time for the trip is 3 hours. What was the speed on each part of the trip?

Answer provided by our tutors

let


d1 = 70 mi the distance of the first part


v = the speed on the first part, v>0


d2 = 6 min the distance of the second part


v - 5 = the speed on the second part, v-5>0 or v>5


since speed = distance/time we have time = distance/speed


we know the total time is 3 hour thus we have:


d1/v + d2/(v - 5) = 3


70/v + 6/(v - 5) = 3


by solving we find:


v = 25.81 mph the speed on the first part of the trip


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v - 5 = 25.81 - 5 = 20.81 mph the speed on the second part of the trip