BOATS & STREAMS – Aptitude Interview Questions with Answers
This blog explains about BOATS & STREAMS – Aptitude Interview Questions with Answers and is given below :
1. 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 place and come back, how far is the place?  
Answer: Option A Explanation: Speed downstream = (5 + 1) kmph = 6 kmph. Speed upstream = (5 – 1) kmph = 4 kmph. Let the required distance be x km.
2x + 3x = 12 5x = 12 x = 2.4 km. 
2 . 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 downstream =  1  x 60  km/hr = 6 km/hr.  
10 
Rate upstream = 2 km/hr.
Speed in still water =  1  (6 + 2) km/hr = 4 km/hr. 
2 
Required time =  5  hrs = 1  1  hrs = 1 hr 15 min.  
4  4 
3 . 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.
4 . 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: 

Answer: Option C Explanation: 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.

Answer: Option B
Explanation:
Let the speed of the stream be x km/hr. Then,
Speed downstream = (15 + x) km/hr,
Speed upstream = (15 – x) km/hr.
30  +  30  = 4  1  
(15 + x)  (15 – x)  2 
900  =  9  
225 – x^{2}  2 
9x^{2} = 225
x^{2} = 25
x = 5 km/hr.
6 . 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?  

Answer: Option C
Explanation:
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.
x x 8  4  = (y x 4)  
5 
44  x =4y  
5 
y =  11  x. 
5 
Required ratio =  y + x  :  y – x  
2  2 
=  16x  x  1  :  6x  x  1  
5  2  5  2 
=  8  :  3 
5  5 
= 8 : 3.
7 .In one hour, a boat goes 11 km/hr along the stream and 5 km/hr against the stream. The speed of the boat in still water (in km/hr) is:  
Answer: Option C Explanation:
Answer: Option B Explanation:

9 .The speed of a boat in still water in 15 km/hr and the rate of current is 3 km/hr. The distance travelled downstream in 12 minutes is:  
Answer: Option D Explanation: Speed downstream = (15 + 3) kmph = 18 kmph.

10 . A boat covers a certain distance downstream in 1 hour, while it comes back in 1 hours. If the speed of the stream be 3 kmph, what is the speed of the boat in still water?  
Answer: Option D Explanation: Let the speed of the boat in still water be x kmph. Then, Speed downstream = (x + 3) kmph, Speed upstream = (x – 3) kmph.
2x + 6 = 3x – 9 x = 15 kmph. 