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.

Bhavesh said:   8 years ago
What is this same Q is like in 3 hours a boat goes 11 km along the stream and 5 km against the stream the speed of the boat in still water is?
(1)

Suresh said:   9 years ago
A boats cover 1 km in 10 minute with stream and 1 km in 20 minute against stream now speed of boat in still water will be?

Please solve it.

Darkele said:   7 years ago
Note, there is no use of the 1 hour given because the upstream and downstream is sufficient to get the speed of the boat in still water.
(3)

HARI said:   7 years ago
For finding the speed of the boat in still water = (upstream-downstream/2).
For finding water speed = (upstream+downstream/2).
(7)

Nikul rana said:   1 decade 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.

Shudhu said:   9 years ago
Downstream so, x + y = 11.
Upstream so, x - y = 5.

Solve equation 1 and 2.

You get x =7.5.

So, nearest answer is 8.

Ayan said:   10 years ago
The question is not clear. It says in one hour both travel upstream as well as downstream. How is it explain me?

Yamini said:   8 years ago
If the speed downstream is a km/hr and speed upstream is b km/hr then,
Speed in still water=1/2(a+b)km/hr.
(1)

Kamala kant said:   8 years ago
Do you have the concept of eqillibrium? then say
if , (11/x +y) + (5/x-y) =3,
x=?

Brinda Iyer said:   1 decade ago
But if in the same question distance traveled is asked, then what is the formula?


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