SOLUTION: Biking into the wind on a flat path, a bicyclist takes 5 hours to travel 30 miles. The return bike takes 3 hours. The wind speed remains constant during the trip. a. Find the bi

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Question 269393: Biking into the wind on a flat path, a bicyclist takes 5 hours to travel 30 miles. The return bike takes 3 hours. The wind speed remains constant during the trip.
a. Find the bicyclist's average speed for each leg of the trip.
b. Write a system of linear equations that represent the situation.
c. What is the bicyclist's average speed in still air? What is the speed of the wind?

Found 2 solutions by josmiceli, Alan3354:
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let w = wind speed
Let b = bike's speed with no wind
The trip that takes less time is with the wind
The 2 equations to use are:
d+=+%28b+-+w%29%2At%5B1%5D (against the wind)
d+=+%28b+%2B+w%29%2At%5B2%5D (with the wind)
given:
d+=+30
t%5B1%5D+=+5 hrs
t%5B2%5D+=+3 hrs
-------------------
The only unknowns are b and w,
so I've got 2 equations and 2 unknowns
(1) 30+=+%28b+-+w%29%2A5
(1) 30+=+5b+-+5w
(1) 6+=+b+-+w
and
(2) 30+=+%28b+%2B+w%29%2A3
(2) 30+=+3b+%2B+3w
(2) 10+=+b+%2B+w
------------------------
Add the equations
(2) 10+=+b+%2B+w
(1) 6+=+b+-+w
16+=+2b
b+=+8
and, since
10+=+b+%2B+w
10+=+8+%2B+w
w+=+2
------------
(a)
The bicyclist's average speed for the 1st leg:
b+-+w+=+8+-+2
b+-+w+=+6 mi/hr
The bicyclist's average speed for the 2nd leg:
b+%2B+w+=+8+%2B+2
b+%2B+w+=+10 mi/hr
----------------------
(b)
b+-+w+=+6
and
b+%2B+w+=+10
-----------------------
(c)
In still air the cyclist's speed is b+=+8 mi/hr
The wind seed is w+=+2 mi/hr




Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
What connection is there between wind speed and bicycle speed?
It's not possible to calculate wind speed from this info.