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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 
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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 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 

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 
Speed of a boat in still water is 10 kmph, and speed of the stream is 5 Kmph. In how many minutes would the boat cover a distance of 5 km downstream? 
A) 20 minute B) 30 minute C) 40 minute D) 25 minute Correct Answer : 20 minute Explanation : boat speed = 10 km/hr and stream speed = 5 km/hr Time taken to travelled 5 km distance time = distance / speed = 5/ 15 = 1/3 hr = 60/3 minutes = 20 minutes 
In one hour, a boat goes 11 km along the stream and 5 km against the stream. The speed of the boat in still water is? 
A) 4km/hr B) 8km/hr C) 12km/hr D) 16km/hr Correct Answer : 8km/hr Explanation : Let A= Downstream=11km/hr , 

A man can row 18 kmph in still water. It takes him thrice as long as row up as to row down the river. find the rate of stream? 
A) 4km/hr B) 8km/hr C) 9km/hr D) 12km/hr Correct Answer : 9km/hr Explanation : Let man’s rate upstream be x kmph Rate upstream, x=9 km/hr, 
A man can row 7.5 kmph in still water. if in a river running at 1.5 km an hour, if takes him 50 min to row to place and back. How far off is the place? 
A) 3 km B) 15 km C) 7 km D) 16 km Correct Answer : 3 km Explanation : Let the place be x kms from starting point. Total time=> x/6 + x/9=50/60 hr The place is at distance of 3 km 
A man can row 3 quarters of a km against the stream is 11(1/4) min. the speed of the man in still water is? 
A) 12 kmph B) 15 kmph C) 5 kmph D) 8 kmph Correct Answer : 5 kmph Explanation : three  quarters of a kilometer = 750 meters rate upstream = 750/625 m/sec =10/9 m/sec 
A boat can travel with a speed of 13 kmph in still water. if the speed of stream is 4 kmph,find the time taken by the boat to go 68 km downstream? 
A) 9 hrs B) 4 hrs C) 2 hrs D) 7 hrs Correct Answer : 4 hrs Explanation : Speed down stream = 13+4 = 17 kmph 
A boat takes 90 min less to travel 36 miles downstream then to travel the same distance upstream. if the speed of the boat in still water is 10 mph .the speed of the stream is ? 
A) 17 mph B) 12 mph C) 6 mph D) 2 mph Correct Answer : 2 mph Explanation : Let the speed of the stream be x mph As given, 36/[10x]  36/[10+x] = 90/60 hrs time cannot be negative. 
At his usual rowing rate, Rahul 12 miles downstream in a certain river in 6 hrs less than it takes him to travel the same distance upstream. but if he could double his usual rowing rate for his 24 miles round the downstream 12 miles would then take only one hour less than the upstream 12 miles. what is the speed of the current in miles per hours? 
A) 2(2/3) mph B) 1(1/3) mph C) 1(2/3) mph D) 2/3 mph Correct Answer : 2(2/3) mph Explanation : Let the speed in still water be x mph and the speed of the current be y mph. 
There is a road beside a river. two friends started from a place A, moved to a temple situated at another place B and then returned to A again. one of them moves on a cycle at a speed of 12 kmph, while the other sails on a boat at a speed of 10 kmph . if the river flows at the speed of 4 kmph , which of the two friends will return to place A first? 
A) Sailor B) Cyclist C) Both D) Data insufficient Correct Answer : Cyclist Explanation : Clearly, The cyclist moves both ways at a speed of 12 kmph Since, the average speed of the cyclist is greater 12 kmph> 8.4 kmph 