Boats and Streams
 A boat goes 14 km upstream in 56 minutes. The speed of stream is 2 km/hr. The speed of boat in still water is ?

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∵ Speed upstream = 14 x (60/56) = 15 km/hr
Speed in upstream = Speed in still water  Speed of stream.Correct Option: D
∵ Speed upstream = 14 x (60/56) = 15 km/hr
Speed in upstream = Speed in still water  Speed of stream.
⇒ x  2 = 15
∴ x = 17 km/hr
 The speed of a boat in still water is 10 km/hr. If its speed down stream be 13 km/hr, then speed of the stream is ?

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Speed in still water + Speed of stream = Speed in downstream.
⇒ 10 + y = 13Correct Option: B
Speed in still water + Speed of stream = Speed in downstream.
⇒ 10 + y = 13
∴ y = 13  10 = 3 km/hr
 The speed of a boat in still water is 12 km per hour. Going downstream it moves at the rate of 19 km per hour. The speed of the boat against the stream is ?

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Speed of stream = speed in downstream  Speed in still water
⇒ Speed of stream = 19  12 = 7 km/hr
Speed of boat against stream = Speed in still water  Speed of stream.
⇒ Speed of boat against stream = 12  7 = 5 km/hrCorrect Option: A
Speed of stream = speed in downstream  Speed in still water
⇒ Speed of stream = 19  12 = 7 km/hr
Speed of boat against stream = Speed in still water  Speed of stream.
⇒ Speed of boat against stream = 12  7 = 5 km/hr
 If a man rows at the rate of 5 km/hr in still water and his rate against the current is 3.5 km/hr, then the man's rate along the current is ?

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Speed of current = 5  3.5 = 1.5 km/hr
Man's speed along the current = Man speed in still water + speed of current.Correct Option: B
Speed of current = 5  3.5 = 1.5 km/hr
Man's speed along the current = Man speed in still water + speed of current.
⇒ Man's speed along the current = 5 + 1.5 = 6.5 km/hr
 A man rows upstream 16 km and downstream 27 km talking 5 hours each time. What is the velocity of current ?

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∵ Man's rate upstream = 16/5 km/hr
Man's rate downstream = 27/5 km/hrCorrect Option: C
Man's rate upstream = 16/5 km/hr
Man's rate downstream = 27/5 km/hr
∴ Velocity of the current = (27/5  16/5)/2 km/hr = 1.1 km/hr