A boatman rows 96 km downstream in 8 hours with a stream speed of 4kmph. How much time will he take to cover 8km upstream?
Answer: C
Speed = distance/time
Speed downstream: 96 / 8 km/hr = 12kmph
Speed of stream = 4kmph
Effective speed of boat = (12-4) kmph
= 8kmph
Distance to be traveled upstream= 8 km
Speed upstream = boat speed-current speed
= 8-4 kmph
= 4 kmph
Time taken = distance/speed = 8/ 4 hours
=2 hours
Thus it will take 2 hours to go upstream.
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The speed of a motor boat is that of the current of water as 36:5. The boat goes along with the current in 5 hours 10 min, it will come back in?
Answer: C
Let the speed of motor boat be 36x km/hr and that of current of water be 5x km/hr
Speed downstream = (36x +5x)km/hr = 41x km/hr
Speed upstream = (36 -5x)km/hr = 31x km/hr
Distance covered downstream = (41x × 31/6)km
Distance upstream = [1271x/6 × 1/31x]hrs
= 41/6 hrs = 6hrs 50 min
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The current of a stream runs at the rate of 4 kmph. A boat goes 6 km and back to the starting point in 2 hours, then find the speed of the boat in still water?
Answer: C
S = 4
M = x
DS = x + 4
US = x - 4
6/(x + 4) + 6/(x - 4) = 2
x = 8
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Find the ratio of swimming speed of Raj in still water to speed of river, if ratio of time taken to go 10km upstream to time taken to go 10km downstream is 11:5?
Answer: C
No answer description available for this question.
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A boat goes 100 km downstream in 10 hours, and 75 m upstream in 15 hours. The speed of the stream is?
Answer: D
No answer description available for this question.
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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
Answer: C
Speed downstreams =(15 + 3)kmph
= 18 kmph.
Distance travelled = (18 x 12/60)km
= 3.6km
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A boat can travel with a speed of 13 km/hr in still water. If the speed of the stream is 4 km/hr, find the time taken by the boat to go 68 km downstream.
Answer: C
Speed downstream = (13 + 4) km/hr = 17 km/hr.
Time taken to travel 68 km downstream = (68/17)hrs = 4 hrs.
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