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A man swims downstream 72 km and upstream 45 km taking 9 hours each time. what is the speed of the current?
A3 kmph
B1.5 kmph
C13 kmph
D6.5 kmph
Answer: Option B
Explanation:Man's downstream speed = 72/ 9 kmph => 8kmph
Man's up stream speed = 45/ 9 => 5 kmph
So speed of current = (8 - 5)/2 = 1.5 kmph
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2 / 38
A boat can row upstream at 25 kmph and downstream at 35 kmph, then the speed of the current is?
A5 kmph
B10 kmph
C30 kmph
D15 kmph
Answer: Option A
Explanation:man's upstream speed = 25 kmph
Man's downstream speed = 35 kmph
so Speed of current = (35 - 25)/2 = 5 kmph
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3 / 38
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 :
A2 km
B2.6 km
C3.6 km
D4 km
Answer: Option C
Explanation:Speed downstream = (15 + 3) kmph = 18 kmph.
Distance travelled = [18 * 12/60] km = 3.6 km.
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4 / 38
A man can row his boat with the stream at 6 km/h and against the stream in 4 km/h. The man's rate is?
A1 kmph
B5 kmph
C8 kmph
D3 kmph
Answer: Option A
Explanation:Man's row in downstream by speed = 6 kmph
and upstream by speed = 4 kmph
so man rate = (6 - 4)/2 = 1 kmph
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5 / 38
A man can row upstream at 8kmph and downstream at 13 kmph. The speed of the stream is
A2.5 km/hr
B4.2 km/hr
C5 km/hr
D10.5 km/hr
Answer: Option A
Explanation:Speed of stream = 1/2(13 -8) kmph = 2.5 kmph.
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6 / 38
A man can swim in still water at 4.5 km/h, but takes twice as long to swim upstream than downstream. The speed of the stream is?
A3
B7.5
C2.25
D1.5
Answer: Option D
Explanation:Swim in still water by speed = 4.5 kmph
Let's assume speed in still water = x kmph
speed in downstream =(4.5 + x) kmph
speed in upstream = (4.5 + x) kmph
Given (4.5 + x) = (4.5 - x)2
4.5 + x = 9 -2x
3x = 4.5
x = 1.5 kmph
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7 / 38
A man can row at 5 kmph in still water. If the velocity of current is 1 kmph and it takes him 1 hour to row to a plce and come back, how far is the place?
A2 km
B2.4 km
C2.5 km
D3.4 km
Answer: Option B
Explanation:Speed downstream = (5+1) kmph = 6 kmph; Speed upstream = (5 - 1)kmph = 4 kmph. Let the required distance be x km.
Then, x/6 + x/4 = 1 ? 2x + 3x = 12 ? 5x = 12 ? x = 2.4 km.
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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
A8.5 km / hr
B9 km / hr
C10 km / hr
D12.5 km / hr
Answer: Option C
Explanation:Man's rate in still in 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.
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A man can row with a speed of 15 kmph in still water. If the stream flows at 5 kmph, then the speed in downstream is?
A10 kmph
B5 kmph
C20 kmph
D22 kmph
Answer: Option C
Explanation:speed in still water = 15 kmph
stream speed = 5 kmph
so Downstream speed = (15 + 5) kmph = 20 kmph
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10 / 38
A man swims downstream 30 km and upstream 18 km taking 3 hours each time, what is the speed of the man in still water?
A2 kmph
B8 kmph
C16 kmph
D4 kmph
Answer: Option B
Explanation:Man's downstream speed = 30/3 kmph = 10 kmph
Man's upstream speed = 18/3 kmph = 6 kmph
Speed of man in still water = (10 + 6)/2 = 8 kmph
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