Aptitude

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_________?

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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_________?

A. 3
B. 7.5
C. 2.25
D. 1.5
Explanation:
M = 4.5
S = x
DS = 4.5 + x
US = 4.5 + x
4.5 + x = (4.5 – x)2
4.5 + x = 9 -2x
3x = 4.5
x = 1.5

A person can swim in still water at 4 km/h. If the speed of water 2 km/h, how many hours will the man take to swim back against the current for 6km?

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A person can swim in still water at 4 km/h. If the speed of water 2 km/h, how many hours will the man take to swim back against the current for 6km?

A. 3
B. 4
C. 4 (1/2)
D. Insufficient data
Explanation:
M = 4
S = 2
US = 4 – 2 = 2
D = 6
T = 6/2 = 3

A man takes twice as long to row a distance against the stream as to row the same distance in favour of the stream. The ratio of the speed of the boat (in still water) and the stream is________?

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A man takes twice as long to row a distance against the stream as to row the same distance in favour of the stream. The ratio of the speed of the boat (in still water) and the stream is________?

A. 2 : 1
B. 3 : 1
C. 3 : 2
D. 4 : 3

Speed of a boat in standing water is 9 kmph and the speed of the stream is 1.5 kmph. A man rows to a place at a distance of 105 km and comes back to the starting point. The total time taken by him is_________?

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Speed of a boat in standing water is 9 kmph and the speed of the stream is 1.5 kmph. A man rows to a place at a distance of 105 km and comes back to the starting point. The total time taken by him is_________?

A. 16 hours
B. 18 hours
C. 20 hours
D. 24 hours

A man can row 9 1/3 km/hr in still water and he finds that is thrice as much time to row u p than as to row down the same distance in river. The speed of the current is:________?

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A man can row 9 1/3 km/hr in still water and he finds that is thrice as much time to row u p than as to row down the same distance in river. The speed of the current is:________?

A. 3 1/3 km/hr
B. 3 1/9 km/hr
C. 1 ¼ km/hr
D. 4 2/3 km/hr
Explanation:
Let Speed upstream = x km/hr
Speed downstream = 3x km/hr
Speed in still water = ½ (x+3x) km/hr = 2x km/hr
Speed of current = ½ (3x-x) km/hr = x km/hr
2x = 28/3 or x = 14/3 = 4 2/3 km/hr