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:
Answer: Option
Explanation:
Discussion:
39 comments Page 2 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)
Sara said:
9 years ago
x = speed of stream still in water.
y = speed of stream.
downstream = Distance/ X+Y = Time,
= 11/ X+Y = 1hour.
Upstream= Distance/ X-Y = Time.
= 5/X-Y = 1hour.
Cross multiply
11 = X + Y -----(1)eq
5 = X - Y ------(2)eq
We need x, so cancel y.
2X = 16,
X = 8kmph.
y = speed of stream.
downstream = Distance/ X+Y = Time,
= 11/ X+Y = 1hour.
Upstream= Distance/ X-Y = Time.
= 5/X-Y = 1hour.
Cross multiply
11 = X + Y -----(1)eq
5 = X - Y ------(2)eq
We need x, so cancel y.
2X = 16,
X = 8kmph.
Shruti said:
9 years ago
How come the speed becomes 11 kmph and 5 kmph when only distance is given, and boat travels both the distances in total 1 hour?
I think either the question is wrong or 8 is not the answer.
I think either the question is wrong or 8 is not the answer.
Aman kumar said:
9 years ago
B = Speed of boat.
w = Speed of water.
NOW
B + W=11 (with the stream)
B - W=5 (opp to stream)
----------------
2B =16,
B =16/2,
= 8 KMPH.
w = Speed of water.
NOW
B + W=11 (with the stream)
B - W=5 (opp to stream)
----------------
2B =16,
B =16/2,
= 8 KMPH.
Suresh said:
8 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.
Please solve it.
Audry said:
8 years ago
Let U= speed of boat in still water and v=speed of stream then;
Upstream speed, U - V = 5km/hr,
Downstream speed, U + V = 11km/hr,
Eqt,
U + V + U - V = 11 + 5
2U = 16
U = 16/2 = 8km/hr.
Upstream speed, U - V = 5km/hr,
Downstream speed, U + V = 11km/hr,
Eqt,
U + V + U - V = 11 + 5
2U = 16
U = 16/2 = 8km/hr.
Satish said:
8 years ago
D=11 U=5.
(D+U)/2=x.
11+5/2=X.
16/2=X.
8=X (stream speed).
(D+U)/2=x.
11+5/2=X.
16/2=X.
8=X (stream speed).
Kamala kant said:
8 years ago
Do you have the concept of eqillibrium? then say
if , (11/x +y) + (5/x-y) =3,
x=?
if , (11/x +y) + (5/x-y) =3,
x=?
A.K.BALAKRISHNAN said:
6 years ago
@All.
Follow this method for all boat question;
Downstream means boat towards the down in this situation we have to find the speed of boat and speed of stream.
Let x be boat speed.
Let y be stream speed.
1) Down stream speed = D/T(downstream time) = x+y
note: distance will be the same as both the streams.
2) Upper stream speed = D/T (upper stream time) = x-y.
Thank you.
Follow this method for all boat question;
Downstream means boat towards the down in this situation we have to find the speed of boat and speed of stream.
Let x be boat speed.
Let y be stream speed.
1) Down stream speed = D/T(downstream time) = x+y
note: distance will be the same as both the streams.
2) Upper stream speed = D/T (upper stream time) = x-y.
Thank you.
Vinayak shelke said:
4 months ago
8 is the answer.
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