Aptitude - Boats and Streams - Discussion

Discussion Forum : Boats and Streams - General Questions (Q.No. 5)
5.
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:
3 km/hr
5 km/hr
8 km/hr
9 km/hr
Answer: Option
Explanation:

Speed in still water = 1 (11 + 5) kmph = 8 kmph.
2

Video Explanation: https://youtu.be/KQX_mA3tcVA

Discussion:
39 comments Page 3 of 4.

Ayan said:   9 years ago
The question is not clear. It says in one hour both travel upstream as well as downstream. How is it explain me?

Nija said:   10 years ago
In this question, it is not mentioned whether 1 hour each taken by downstream and upstream. So how can we solve this questions ? Please am confused.

Priya said:   10 years ago
What is this? Am not clear, I am late pick up person, say clearly guys.

Nikul rana said:   10 years ago
Speed downstream = X+Y = 11 kmph;

Speed upstream = X-Y = 5 kmph;

Speed of the still water = (X+Y)+(X-Y)*1/2 = 8 kmph.

Suchita said:   10 years ago
Because in question they have mentioned speed of boat along the stream (i.e downstream) is 11km/hr and against the stream (i.e upstream) is 5km/hr.

Ramachandran said:   1 decade ago
Hello guys how would you find:

11 km/hr is Downstream.
5 km/hr is Upstream.

Naresh said:   1 decade ago
Given that,

Speed in the downstream (d) = 11 km/hr.

Speed in the upstream (u) = 5 km/hr.

Speed of the Boat in still water = d + u/2.

=> 11 + 5/2 = 16/2.

=> 8 km/hr.

Subaram said:   1 decade ago
Here direction along the stream called downstream and against the stream called upstream. In this question they gave along the stream 11 kmhr against the stream 5 kmhr. So speed still in water = 1/2 (a+b) , here a downstream be up stream as for formula.
(1)

Mina said:   1 decade ago
What is u and v?

Arun.D said:   1 decade ago
Downstream=11km/hr.
Upstream=5km/hr.
Speed in still water = 1/2(a + b) km/hr.

a = upstream.

b = downstream.

Speed = 1/2(11+5)km/hr.
= 1/2(16)km/hr.
= 8km/hr.


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