SOLUTION: a boat traveled 60 mi down river and then returned. the total time for the round trip was 5 hr. the rate of the current was 5 mph. find the rate of the boat in still water
SPEED TIME DISTANCE
DOWN r+5 60
RETURN r-5 60
Total 5
Solve this time sum equation: Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website! Let = time spent going down river = time spent going up river
Let = the rate of the boat in still water = the rate of the boat going down riover = the rate of the boat going up river
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Going down river:
(1)
Going up river:
(2)
----------------------------
(1)
and
(2)
(2)
Substitute (1) into (2)
(2)
(2)
Multiply both sides by
(2)
(2)
(2)
(2)
(2) ( can't use the other solution )
The rate of the boat in still water is 25 mi/hr
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check:
(1)
(1)
(1)
(1)
(2)
(2)
(2)
(2) hrs
OK