Exercise :: Boats and Streams  General Questions
 Boats and Streams  Important Formulas
 Boats and Streams  General Questions
 Boats and Streams  Data Sufficiency 1
 Boats and Streams  Data Sufficiency 2
11.  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? 

Answer: Option C Explanation:
Rate upstream = 2 km/hr.

12.  A man can row threequarters of a kilometre against the stream in 11 minutes and down the stream in 7 minutes. The speed (in km/hr) of the man in still water is: 

Answer: Option D Explanation: We can write threequarters of a kilometre as 750 metres, and 11 minutes as 675 seconds.
= 5 km/hr. 
13.  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: 

Answer: Option D Explanation: Speed upstream = 7.5 kmph. Speed downstream = 10.5 kmph.

14.  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: 

Answer: Option B Explanation: Let man's rate upstream be x kmph. Then, his rate downstream = 2x kmph.
= 3 : 1. 
15.  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: 

Answer: Option A Explanation: Suppose he move 4 km downstream in x hours. Then,
So, Speed downstream = 8 km/hr, Speed upstream = 6 km/hr.
