Question 169934: A boat can travel 36 mmiles downstream in 2 hours. Coming back upstream the trip takes 3 hours. Find the rate of the boat in still water and the rate of the current.
b be average speed of boat,
c = average current.
gives
2(b+c)= 36
3(b-c)= 36
expanding
..
2b+2c=36....divide by 2, b+c=18 giving 3b+3c=54
3b-3c=36..given
..
3b+3c=54...eqn 1
3b-3c=36...eqn 2
subtract eqn 2 from 1
6c=18
c=3
b=15
Rate of boat = 15 mph
Current = 3mph
Answer by rajagopalan(174)   (Show Source):
You can put this solution on YOUR website! Let
b be average speed of boat,
c = average current.
gives
2(b+c)= 36
3(b-c)= 36
expanding
..
2b+2c=36....divide by 2, b+c=18 giving 3b+3c=54
3b-3c=36..given
..
3b+3c=54...eqn 1
3b-3c=36...eqn 2
subtract eqn 2 from 1
6c=18
c=3
b=15
...
Answer:
Rate of boat = 15 mph
Current = 3mph
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