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 12 of 12.
M Danish said:
4 weeks ago
Assume distance as 100 km.
Calculate Speed @ downstream (100/4hrs) = 25 km/h
Calculate speed @ upstream ( 100/ 8.8 hrs) = 11.36 km/h
Take the difference of both and divide by 2 to get the speed of the river.
(13.64/2)= 6.82 km/h.
To calculate the speed of the boat minus the speed of the river, from speed @ downstream (25-6.82) = 18.18 km/h.
Now as you have both speeds, calculate the ratio (18.18/6.82) = 2.66 = 8/3.
Calculate Speed @ downstream (100/4hrs) = 25 km/h
Calculate speed @ upstream ( 100/ 8.8 hrs) = 11.36 km/h
Take the difference of both and divide by 2 to get the speed of the river.
(13.64/2)= 6.82 km/h.
To calculate the speed of the boat minus the speed of the river, from speed @ downstream (25-6.82) = 18.18 km/h.
Now as you have both speeds, calculate the ratio (18.18/6.82) = 2.66 = 8/3.
(2)
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers