SOLUTION: During a trip a kayaker travel 12 miles upstream against the current in 3 hours. he then return with the current, to the starting point in two hours. The speed of the current remai

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Question 966545: During a trip a kayaker travel 12 miles upstream against the current in 3 hours. he then return with the current, to the starting point in two hours. The speed of the current remained constant during the entire trip. what was the average speed of the kayaker and the speed of the current
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
+s+ = speed of kayak in still water
+c+ = the speed of the current
---------------------------------
Going upstream:
(1) +12+=+%28+s+-+c+%29%2A3+
Going downstream:
(2) +12+=+%28+s+%2B+c+%29%2A2+
-----------------------
(1) +3s+-+3c+=+12+
(2) +2s+%2B+2c+=+12+
---------------------
(1) +s+-+c+=+4+
(2) +s+%2B+c+=+6+
-------------------
+2s+=+10+
+s+=+5+
and
(1) +s+-+c+=+4+
(1) +5+-+c+=+4+
(1) +c+=+1+
----------------
The speed of the current is 1 mi/hr
----------------
The average speed of the kayaker is:
[ total distance ] / [ total time ]
+%28+12+%2B+12+%29+%2F+%28+3+%2B+2+%29+
+24%2F5+=+4.8+ mi/hr