The speed of a boat in still water in 22 km/hr and the rate of current is 4 km/hr. The distance travelled downstream in 24 minutes is:
Speed downstream = (22 + 4) kmph = 26 kmph.
Distance travelled = 26 x 24/60
Distance travelled = 10.4 km
A boat running upstream takes 8 hours 48 minutes to cover a certain distance, while it takes 4 hours to cover the same distance running downstream. What is the ratio between the speed of the boat and speed of the water current respectively?
Let the man's rate upstream be x kmph and that downstream be y kmph.
Then, distance covered upstream in 8 hrs 48 min = Distance covered downstream in 4 hrs.
Speed of a boat in standing water is 14 kmph and the speed of the stream is 1.2 kmph. A man rows to a place at a distance of 4864 km and comes back to the starting point. The total time taken by him is:
Speed downstream = (14 + 1.2)
= 15.2kmph
Speed upstream = (14-1.2)
= 12.8kmph
Total time taken = 4864/15.2 + 4864/12.8
= 320 + 380
= 700hrs
Q. A man's speed with the current is 15 km/hr and the speed of the current is 2.5 km/hr. The man's speed against the current is:
Man's rate in still water = (15 - 2.5) km/hr = 12.5 km/hr.
Man's rate against the current = (12.5 - 2.5) km/hr = 10 km/hr.
A man rows to a place 48 km distant and come back in 14 hours. He finds that he can row 4 km with the stream in the same time as 3 km against the stream. The rate of the stream is:
Suppose he move 4 km downstream in x hours. Then,
Speed downstream =
Speed upstream =
So, Speed downstream = 8 km/hr, Speed upstream = 6 km/hr.
A motorboat, whose speed in 15 km/hr in still water goes 30 km downstream and comes back in a total of 4 hours 30 minutes. The speed of the stream (in km/hr) is:
Let the speed of the stream be x km/hr. Then,
Speed downstream = (15 + x) km/hr,
Speed upstream = (15 - x) km/hr.
⇒ 9x2 = 225
⇒ x2 = 25
⇒ x = 5 km/hr.
A boatman goes 2 km against the current of the stream in 1 hour and goes 1 km along the current in 10 minutes. How long will it take to go 5 km in stationary water?
Rate downstream =
Rate upstream = 2 km/hr.
Speed in still water =
Required time =
A boat can travel with a speed of 22 km/hr in still water. If the speed of the stream is 5 km/hr, find the time taken by the boat to go 54 km downstream.
Speed downstream = (22 + 5) km/hr = 27 km/hr.
Time taken to travel 54 km downstream = (54/27) hours
= 2 hours
In one hour, a boat goes 14 km/hr along the stream and 8 km/hr against the stream. The speed of the boat in still water (in km/hr) is:
Speed in still water = = 8 kmph.
In one hour, a boat goes 14 km/hr along the stream and 8 km/hr against the stream. The speed of the boat in still water (in km/hr) is:
Speed in still water = 1/2 (14 + 8) km/hr
= 11 km/hr
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