SOLUTION: A man travels at 4km/h in still water. If the speed of water current is 1 km/h.It takes 4 hours to reach the place and come back.How far is the place?

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Question 1187161: A man travels at 4km/h in still water. If the speed of water current is 1 km/h.It takes 4 hours to reach the place and come back.How far is the place?
Found 2 solutions by ikleyn, Alan3354:
Answer by ikleyn(52781) About Me  (Show Source):
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A man travels at 4km/h in still water. If the speed of water current is 1 km/h.
It takes 4 hours to reach the place and come back. How far is the place?
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The effective speed traveling downstream is 4 km/h + 1 km/h = 5 km/h;

The effective speed traveling   upstream is 4 km/h - 1 km/h = 3 km/h.


Let d be the one way distance, in kilometers.


The travel time downstream is  d%2F5  hours;  upstream  d%2F3  hours.


The total time is 4 hours, giving the "time" equation


    d%2F5 + d%2F3 = 4.


To solve it, multiply both sides by 5*3 = 15.  You will get then


    3d + 5d = 4*15

      8d    = 60

       d    = 60/8 = 7.5 kilometers.


ANSWER.  One way distance is 7.5 kilometers.


CHECK.   7.5%2F5 + 7.5%2F3 = 1.5 + 2.5 = 4 hours.    ! Correct !

Solved.



Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
A man travels at 4km/h in still water. If the speed of water current is 1 km/h.It takes 4 hours to reach the place and come back.How far is the place?
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His speed upstream is 4-1 = 3 km/hr
Downstream is 4+1 = 5 km/hr
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Avg speed for any round trip is 2%2Av%5B1%5D%2Av%5B2%5D%2F%28v%5B1%5D+%2B+v%5B2%5D%29
the average speed for the round-trip is 2*3*5/(3+5) = 15/4 km/hr
4*15/4 = 15 km RT, or 7.5 km each way