A motor boat whose speed is 18km/hr in still water takes 1hr more to go 24km upstream than to return downstream to the same spot. What is the speed of the stream?
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Answered by
4
18(x+1)=24(x-1)
18x+18=24x-24
18x-24x=-24-18
-6x=-42
x=42/6
x=7
therefore speed of streamer is 7km/hr
18x+18=24x-24
18x-24x=-24-18
-6x=-42
x=42/6
x=7
therefore speed of streamer is 7km/hr
adi202:
sry wrong ans
Answered by
4
Speed of Motorboat in still water= 18km/hr
Speed of stream= s km/hr
Effective Speed of motorboat when it goes upstream= 18-s
Effective speed of motorboat when is goes downstream= 18+s
Since time taken equals distance travelled divided by speed,
Time taken to travel 24km upstream= 24/(18-s)
Time taken to travel 24km downstream= 24/(18+s)
According to the question, boat takes one hour more when it travels 24km upstream compared to downstream, so
{24/(18-s)} - {24/(18+s)} = 1
Solving this equation, you get s= 6 km/hr
Speed of stream= s km/hr
Effective Speed of motorboat when it goes upstream= 18-s
Effective speed of motorboat when is goes downstream= 18+s
Since time taken equals distance travelled divided by speed,
Time taken to travel 24km upstream= 24/(18-s)
Time taken to travel 24km downstream= 24/(18+s)
According to the question, boat takes one hour more when it travels 24km upstream compared to downstream, so
{24/(18-s)} - {24/(18+s)} = 1
Solving this equation, you get s= 6 km/hr
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