The speed of a boat in still water is 11 km/h. It can go 12 Km upstream and return downstream to the original point in 2 hours 45 minutes. Find the speed of the stream.
Answers
Let the speed of stream be x
Speed of boat in still water = 11
Speed of boat upstream = 11-x
Speed of boat downstream = 11+x
Distance = 12
Distance/speed = time
12/(11-x) + 12/(11+x) = 2 hours 45min
12*(22/(121-x^2) = 11/4
x^2 = 25
x = 5
Speed of stream = 5km/hr
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Answer:
5km/hrs
Step-by-step explanation:
Let the speed of the stream =x km/hr Speed of the boat in still water = 11 km/hr
Speed of the boat downstream = (11 + x) km/hr
Speed of the boat upstream = (11 - x) km/hr
According to the given information,
=>12/11+x+12/11-x = 2*45/60
=> 12[11-x+11+x/121-x^2] = 11/4
=>12*22/121-x^2 = 11/4
=>121 - x^2 = 96
=> x^2 = 25
=> x = 5
Rejecting negative value, as speed cannot be negative. So, x = 5.
Hence, the speed of the stream is 5 km/h