Problema Solution
During the first part of a trip, a canoeist travels 32 miles at a certain speed. The canoeist travels 11 miles on the second part of the trip at a speed 5 mph slower. The total time of the trip is 3 hours. What was the speed on each part of the trip?
Answer provided by our tutors
During the first part of a trip, a canoeist travels 32 miles at a certain speed. The canoeist travels 8 miles on the second part of the trip at a speed 5 mph slower. The total time for this trip is 2 hours. What was the speed on each part of the trip?
Time for 1st part of trip + time for 2nd part of trip = 2 hours
Let x = speed for 1st part of trip
(x - 5) = speed for 2nd part of trip
Distance = speed * time
1st part of trip
32 = x * time #1
Time #1 = 32/x
2nd part of trip
8 = (x - 5) * time #2
Time #2 = 8/(x - 5)
Time #1 + Time #2 = 2
32/x + 8/(x - 5) = 2
both sides by x * (x - 5)
32 * (x - 5) + 8x = 2 * x * (x - 5)
32x - 160 + 8x = 2x^2 - 10x
40x - 160 = 2x^2 - 10x
50x - 160 = 2x^2
2x^2 - 50x + 160 = 0
Divide by 2
x^2 - 25x + 80 = 0