SOLUTION: Ian paddled a canoe 7 miles upstream in a river that has a current of 4 mph. He then turned around and paddled downstream until he reached his original starting place. If the entir
Algebra.Com
Question 813203: Ian paddled a canoe 7 miles upstream in a river that has a current of 4 mph. He then turned around and paddled downstream until he reached his original starting place. If the entire trip took him 6 hours, how fast would Ian paddle in still water?
Found 2 solutions by stanbon, richwmiller:
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
Ian paddled a canoe 7 miles upstream in a river that has a current of 4 mph. He then turned around and paddled downstream until he reached his original starting place. If the entire trip took him 6 hours, how fast would Ian paddle in still water?
---------------
Upstream DATA:
distance = 7 miles ; rate = b-4 mph ; time = d/r = 7/(b-4) hrs
-------------------
Downstream DATA:
distance = 7 miles ; rate = b+4 mph ; time = d/r = 7/(b+4) hrs
------------------------
Equation:
time + time = 6 hrs
7/(b-4) + 7/(b+4) = 6
-------
7(b+4) + 7(b-4) = 6(b^2-16)
14b = 6b^2 - 96
----------
3b^2 - 7b -48 = 0
------------
Positive solution::
b = 5 1/3 mph (Ian's rate in still water)
======================
Cheers,
Stan H.
======================
Answer by richwmiller(17219) (Show Source): You can put this solution on YOUR website!
a+b=6,
(r+4)*a=7,
(r-4)*b=7
a = 3/4, b = 21/4, r = 16/3
RELATED QUESTIONS
Chance paddled a canoe 10 miles upstream in a river that has a current of 4 mph. He then... (answered by josmiceli)
Andres paddled a canoe 11 miles upstream in a river that has a current of 4 mph. He then... (answered by TimothyLamb)
Bill paddled a canoe 2 miles upstream in a river that has a current of 2 mph. He then... (answered by stanbon)
Zach paddled a canoe 2 miles upstream in a river that has a current of 3 mph. He then... (answered by TimothyLamb)
Jake paddled a canoe 4 miles upstream at a constant speed of 10 mph. He then turned... (answered by ankor@dixie-net.com)
Ian and Spencer paddeled their canoe downstream at a rate of 8 mph. They then turned... (answered by josgarithmetic)
mario paddled his caneo upstream for 3 hours. when he turned around and paddled back to... (answered by stanbon)
One day last summer, Jim went kayaking on the Little Susitna River in Alaska. Paddling... (answered by ankor@dixie-net.com)
Peter paddled a canoe 20 miles upstream, then paddled the canoe back to the starting... (answered by lwsshak3)