SOLUTION: A man can row a boat four miles per hour in still water. If he can row downstream 3 times as fast as he can row upstream, find the rate of the current.

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Question 888146: A man can row a boat four miles per hour in still water. If he can row downstream 3 times as fast as he can row upstream, find the rate of the current.
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +c+ = the rate of the current
+4+%2B+c+ = man's rate going downstream
+4+-+c+ = man's rate going upstream
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+4+%2B+c+=+3%2A%28+4+-+c+%29+
+4+%2B+c+=+12+-+3c+
+4c+=+8+
+c+=+2+
The rate of the current is 2 mi/hr
check:
+4+%2B+c+=+3%2A%28+4+-+c+%29+
+4+%2B+2+=+3%2A%28+4+-+2+%29+
+6+=+3%2A2+
+6+=+6+
OK