Quantitative Aptitude-Boats and Streams updated on Aug 2020
Boats and Streams problems are frequently asked problems in competitive exams. Many different types of questions can be framed out of boat and stream problems. In order to solve elementary questions on Boats and Streams in the competitive exmas, candidates should use the fundamental concepts of time speed and distance only.

Boats and Streams-Boats and Streams

|   40387

 

Boats and Streams  Aptitude basics, practice questions, answers and explanations 
Prepare for companies tests and interviews

Boats and Streams 

The water of a stream, usually, keeps flowing at a certain speed, in a particular direction. This speed is called the current of the stream. A boat develops speed because of its engine power. The speed with which it travels when there is no current is called speed of boat in still water. When the boat moves in the direction of the current is said to be with the stream/ current or downstream. When the boat moves in the direction opposite to that of the current, it is said to be against the stream is called upstream.

Eg:-If the speed of a boat in still water is ‘u’km/hr and the speed of the stream is ‘v’km/hr then:


* Speed downstream=(u+v)km/hr

* Speed upstream = (u-v)km/hr

If the speed downstream is u km/hr and the speed upstream is v km/hr, then: 

* Speed of boat in still water = ½(u+v)km/hr

* Speed (Rate) of stream = ½ (u-v)km/hr 

Examples 

a) A man can row a boat 12 km/h with the stream and 8km/h against the stream.

Find his speed in still water. 

a) 2km/hr 
b) 4km/hr 
c) 8km/hr 
d) 10km/hr


Solution: Speed of boat in still water = ½(u+v) km/hr = ½ (12+8)=10km/hr

b) A man can row a boat 27km/h with the stream and 11km/h against the stream.

Find speed of stream 

a) 2km/hr 
b)4km/hr 
c)8km/hr 
d)10km/hr


Solution: Speed (Rate) of stream = ½ (u-v) km/hr = ½ (27-11)=8km/hr

c) A boat running downstream covers a distance of 16km in 2 hours while for covering the same distance upstream, it takes 4 hours. What is the speed of the boat in still water? 

a)4km/hr 
b)6km/hr 
c)8km/hr 
d) None of these 

Rate of downstream=(16/2 ) kmph=8kmph
Rate of upstream =(16/4) kmph=4kmph
Therefore Speed in still water=1/2(8+4) kmph=6kmph 


Note: If ratio of downstream and upstream speeds of a boat is ‘a:b.’

Then ratio of time taken= b:a

Speed of stream=a-b/a+b *Speed in still water

Speed in still water =a+b/a-b *Speed of stream


Exercise Questions

1. A man rows downstream 32 km and 14km upstream. If he takes 6 hours to cover each distance, then the velocity (in kmph) of the current is:


a)1/2 
b)1 
c)1and ½ 
d)2


Solution: Rate downstream=(32/6)kmph; Rate upstream=(14/6)kmph
Velocity of current=1/2(32/6-14/6)kmph=3/2kmph=1.5kmph


2. In one hour, a boat goes 11km along the stream and 5km against the stream.

The speed of the boat in still water (in km/hr)is:

a)3 
b)5 
c)8 
d)9

Solution: Speed in still water=1/2(11+5)kmph=8kmph

3. Speed of a boat in still water is 16km/h. If it can travel 20km downstream in the same time as it can travel 12 km upstream, the rate of stream is. 

a)1km/h 
b)2km/h 
c)4km/h 
d)5km/h

Solution: Speed downstream: Speed upstream=20:12=5:3


Speed of current=5-3/5+3*16=4km/h

107 reads

 

 

 

 

 

 

 

 

 

Boats and Streams problems are frequently asked problems in competitive exams. Many different types of questions can be framed out of boat and stream problems. In order to solve elementary questions on Boats and Streams in the competitive exmas, candidates should use the fundamental concepts of time speed and distance only. However, some types of difficult problems are tricky and take lots of time to solve by applying textbook approach. These useful tricks, formula and shortcuts are given by freshersworld. Freshersworld.com provides with Boats and Streams - Aptitude Questions and Answers with Explanation, test, solved examples that would help candidates in clearing all the placement papers and competitive tests. It also provides online test on Boats and Streams- quantitative Aptitude. What is upstream and downstream in maths? When the direction of the moving boat and the direction of the stream is opposite, then the boat is in upstream. On the other hand, when direction of the moving boat and the direction of the stream is same, then the boat is in downstream. How do you calculate the average speed of a boat? Upstream Speed * Downstream Speed / Speed of boat in still water
feedback