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The speed of a boat in downstream is 12 km / h and in upstream is 8 km / h. The time taken by boat to cover 24 km in still water? 
A) 2 hours
B) 3 hours
C) 2.4 hours
D) 1.2 hours
Correct Answer : 2 hours Explanation : If The speed of boat or boatman in still water is U kmph and The speed of water or stream is V kmph, then: After solving above equations 2*U = 20 km/hr 
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If a man rows at 5 km/hr in still water and 3.5 km/hr against the current,then his rate along the current is ? 
A) 8.5 km/hr
B) 6.5 km/hr
C) 6 km/hr
D) 4.25 km/hr
Correct Answer : 6.5 km/hr Explanation : If The speed of boat or boatman in calm water is u kmph and The speed of water or stream is v kmph, then:In water, the speed along with stream= (u + v) kmph Speed of current = 5  3.5 = 1.5 km/hr. So the speed of man along the current = 5 + 1.5 = 6.5 km/hr 
The speed of a boat downstream is 15 km/hr and the speed of the stream is 1.5 km/hr. The speed of the boat upstream is ? 
A) 13.5 km/hr
B) 16.5 km/hr
C) 12 km/hr
D) 8.25 km/hr
Correct Answer : 12 km/hr Explanation : If The speed of boat or boatman in calm water is u kmph and The speed of water or stream is v kmph, then: 15= u + 1.5 
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 ? 
A) 6 km/hr
B) 15 km/hr
C) 14 km/hr
D) 17 km/hr
Correct Answer : 17 km/hr Explanation : Speed upstream Speed(S) = Distance(d)/Time(t) = 14/56 km/min = 14*60/56 km/hr= 15 km/hr 
A man can row upstream 32 km in 4 hours. If the speed of current is 2 km/hr, find how much he can go downstream in 6 hours ? 
A) 70 km
B) 72 km
C) 64 km
D) 81 km
Correct Answer : 72 km Explanation : Upstream Speed(S) = Distance(d)/Time(t) = 32/4 km/hr= 8 km/hr If The speed of boat or boatman in still water is U kmph and The speed of water or stream is V kmph, then: 
A man can row upstream at 15 km/h and downstream at 21 km/h. The speed of water current of the river is ? 
A) 8 km/h
B) 6 km/h
C) 3 km/h
D) 5 km/h
Correct Answer : 3 km/h Explanation : If the speed downstream is x kmph and the speed upstream is y kmph, then: = 1/2(21  15) km/h 
A man rows downstream 60 km and upstream 36 km, taking 4 hours each time. The speed of the man is : 
A) 15 km/h
B) 16 km/h
C) 8 km/h
D) 12 km/h
Correct Answer : 12 km/h Explanation : If the speed downstream is x kmph and the speed upstream is y kmph, then: x = 60/4 =15 km/h 

The speed of a boat in still water is 15 km/hr and the rate of current is 3 km/hr. The distance travelled downstream in 12 minutes is? 
A) 1.2 km
B) 1.8 km
C) 2.4 km
D) 3.6 km
Correct Answer : 3.6 km Explanation : Speed Downstream = (15 + 3) km/hr = 18 km/hr. Distance travelled =(18 * 12 / 60 )hrs = 3.6 km 