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:
107 comments Page 11 of 11.
PHANI said:
1 decade ago
Thanks Ashis.
Bharath said:
1 decade ago
Given is 8 hr 48min so converting min to hr
We have 48/60=4/5
We have 48/60=4/5
Ravi said:
1 decade ago
I didn't understand how 8*4/5 will get.
Ashis said:
1 decade ago
As it is given to find out the ratio of speed of boat to speed of water w.r.to still water that is how required ratio is calculated.
You can find out from important formulae option i.e.
1/2(y-x)/1/2(y+x)
where y=speed at downstrem
x=speed at upstream.
You can find out from important formulae option i.e.
1/2(y-x)/1/2(y+x)
where y=speed at downstrem
x=speed at upstream.
Saranya said:
1 decade ago
Can you explain the process clearly?
Pradeesh said:
1 decade ago
How can the y-x/2 become the current ratio?
Anish said:
1 decade ago
How this required ratio? pls explain?
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