SOLUTION: going down the river a boat went 10mph. going up the river it only went 2mph. find the current and the speed of the boat if there were no current.

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Question 497590: going down the river a boat went 10mph. going up the river it only went 2mph. find the current and the speed of the boat if there were no current.
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let c = the speed of the current
Let +b = the speed of the boat in still water
Going downriver, the boat travels at +b+%2B+c+ mi/hr
Going upriver, the boat travels at +b+-+c+ mi/hr
-----------------
given:
going downriver,
(1) +b+%2B+c+=+10+ mi/hr
going upriver,,
(2) +b+-+c+=+2+ mi/hr
-----------------
(1) +c+=+10+-+b+
Substitute this into (2)
(2) +b+-+%28+10+-+b+%29+=+2+
(2) +b+-+10+%2B+b+=+2+
(2) +2b+=+12+
(2) +b+=+6+
The speed of the boat if there is no current is 6 mi/hr