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:
109 comments Page 6 of 11.
Praveen kumar said:
8 years ago
I don't understand why the factor 1/2 comes at the last while calculating the speed of the boat in upstream and downstream { (x+y) /2: (x-y) /2}?
Soumyarahul said:
6 years ago
First, convert the hours into a minute.
528 mints &240mts.
while simplifying the above minutes,
we get,
11 and 5.
11+5/2 :11-5/2.
8:3.
528 mints &240mts.
while simplifying the above minutes,
we get,
11 and 5.
11+5/2 :11-5/2.
8:3.
(1)
Likitha Ganta said:
2 years ago
(x-y)8*48/60 = (x+y)4,
(x-y)8*4/5 = (x+y)4,
(44/5)x-(44/5)y = 4x+4y,
(44/5)x-4x = 4y+(44/5)y,
(44x-20x)/5 = (20y+44y)/5,
24x = 64y,
= 3 : 8.
(x-y)8*4/5 = (x+y)4,
(44/5)x-(44/5)y = 4x+4y,
(44/5)x-4x = 4y+(44/5)y,
(44x-20x)/5 = (20y+44y)/5,
24x = 64y,
= 3 : 8.
(27)
Sangu said:
1 decade ago
Its the ratio between speed of the upstream and speed of the down stream.
Formula is (a+b)/2:(a-b)/2.
See the formula you will get it.
Formula is (a+b)/2:(a-b)/2.
See the formula you will get it.
Ashwini said:
1 decade ago
@Nitin Gusain.
Thanks yaar. It's so simple calculation.
But X-Y = -2 (Stream speed) So instead of that,
Y-X = +2 (Stream speed).
Thanks yaar. It's so simple calculation.
But X-Y = -2 (Stream speed) So instead of that,
Y-X = +2 (Stream speed).
Aman sankhyan said:
4 years ago
@All.
You did not mention which speed of the boat to be calculated if it was in the still water or downstream or against the stream!
You did not mention which speed of the boat to be calculated if it was in the still water or downstream or against the stream!
(3)
Marak said:
4 years ago
8*4/5 will give 44/5 only which is not equal to 8hr 48min.
Please someone explain it to me, how 8hr 48min, how it becomes 8*4/5?
Please someone explain it to me, how 8hr 48min, how it becomes 8*4/5?
Jessie said:
1 decade ago
How does the upstream:downstream relates the ratio speed of the boat:speed of the water current as asked in question?
Anchal said:
1 decade ago
I am not able to understand the required ratio. ? how it is related with the speed of boat to speed of water. ?
Sandeep said:
1 decade ago
x/y = 5/11.
So, x=5 , y=11.
(x+y)/2 : (x-y)/2.
(11+5)/2 : (11-5)/2.
16/2 : 6/2.
8:3 answer.
So, x=5 , y=11.
(x+y)/2 : (x-y)/2.
(11+5)/2 : (11-5)/2.
16/2 : 6/2.
8:3 answer.
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