Aptitude - Boats and Streams - Discussion
Discussion Forum : Boats and Streams - General Questions (Q.No. 3)
3.
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
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.
Discussion:
111 comments Page 5 of 12.
Ajit said:
6 years ago
Just look simple method:
Upward= 8 hr + 48 Min. = 8+48/60 = 44/5.
Downward = 4 hr.
Speed of stream = (44/5 -4)/2 = 2.4 hr.
Speed of boat = 4+2.4 = 6.4 hr.
So, Ratio is 6.4:2.4.
i.e 8:3.
Upward= 8 hr + 48 Min. = 8+48/60 = 44/5.
Downward = 4 hr.
Speed of stream = (44/5 -4)/2 = 2.4 hr.
Speed of boat = 4+2.4 = 6.4 hr.
So, Ratio is 6.4:2.4.
i.e 8:3.
(6)
Prasanth said:
1 decade ago
@Binza
your explantation is not correct. This is not train problem to take like that. Speed of boat supported by extra speed of water current when down stream and reduced in up stream.
your explantation is not correct. This is not train problem to take like that. Speed of boat supported by extra speed of water current when down stream and reduced in up stream.
K srinivasarao said:
1 year ago
U. S = 8hrs * 60 + 48min = 528min
D. S = 4hrs * 60 = 240min.
Ratio = boat of speed=water speed
Boat speed= 528 + 240 = 768.
Water speed = 528 - 240 = 288.
Ratio = 768 : 288 = 8 : 3.
D. S = 4hrs * 60 = 240min.
Ratio = boat of speed=water speed
Boat speed= 528 + 240 = 768.
Water speed = 528 - 240 = 288.
Ratio = 768 : 288 = 8 : 3.
(85)
Sunil babu said:
2 years ago
@Mallika B.
They have x = speed of the boat - speed of the current.
And y = speed of boat + speed of the current.
So y - × = 2 * (speed of boat),
Then (y-x)/2 = speed of the boat.
They have x = speed of the boat - speed of the current.
And y = speed of boat + speed of the current.
So y - × = 2 * (speed of boat),
Then (y-x)/2 = speed of the boat.
(9)
Vikas verma said:
1 decade ago
Let the speed of the Boat be X kmph and Speed of the stream be Y kmph.
Then 44/5 * (X-Y) = 4 * (X+Y).
By solving the equation you will get X/Y = 8:3.
I hope you'll understand.
Then 44/5 * (X-Y) = 4 * (X+Y).
By solving the equation you will get X/Y = 8:3.
I hope you'll understand.
(1)
Arjun said:
1 decade ago
@Jessie.
The stream of the boat is also influenced by the flow of the current, and moreover given here is with the relationship of the boat speed with the current.
The stream of the boat is also influenced by the flow of the current, and moreover given here is with the relationship of the boat speed with the current.
Mallika B said:
2 years ago
Can somebody please explain why have we done (y-x/2) in the required ratio step? If that is associated with downstream, why are we subtracting?
Please explain me.
Please explain me.
(5)
Tushar Pawar said:
3 years ago
Distance Upstream = Distance Downstream.
Speed Upstream * Time Upstream = Speed Downstream * Time Downstream.
(x - y) * 44/5 = (x + y) * 4,
24x = 64y,
x:y = 8:3.
Speed Upstream * Time Upstream = Speed Downstream * Time Downstream.
(x - y) * 44/5 = (x + y) * 4,
24x = 64y,
x:y = 8:3.
(126)
Manikandan said:
8 years ago
For required ratio:
The speed of boat:speed of current.
(u+v)/2 : (u-v)/2.
Here:y=11x/5 =u,
(11x/5+x)/2:(11x/5-x) //take LCM,
16x/5:6x/5,
16x:6x,
8:3.
The speed of boat:speed of current.
(u+v)/2 : (u-v)/2.
Here:y=11x/5 =u,
(11x/5+x)/2:(11x/5-x) //take LCM,
16x/5:6x/5,
16x:6x,
8:3.
Papesh roul said:
1 decade ago
Let the speed of the Boat be: a kmph and Speed of the stream be: b kmph.
Distance =44/5 * (a-b) = 4 * (a+b).
By this equation we will get a/b = 8:3.
Distance =44/5 * (a-b) = 4 * (a+b).
By this equation we will get a/b = 8:3.
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