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 5 of 11.
Rakesh said:
1 decade ago
@sangu
Thank u a lot..
Thank u a lot..
Gautam said:
1 decade ago
Let the man's rate upstream be U kmph and that downstream be V kmph.
Then, distance covered upstream in 8 hrs 48 min = Distance covered downstream in 4 hrs.
[U*8*48/60] = [V*4] [BECAUSE 1 MINUTE=60SECONDS]
[U*8*4/5] = [4V]
[U*44/5] = [4V]
44/5 U = 4V
THEN, USE THE FORMULA-----If the speed of the boat in still water is U km/hr and the stream of the boat is V km/hr then.
speed downstream = (u+v)km/hr
speed up stream = (u+v)km/hr
so, our U= 44/5 COME AND V= 4 COME
NOW, [U+V]/[U-V]
[44/5+4] / [44/5-4]
[44+20] / [44-20]
64/24,
8/3,
8:3 ANS
Then, distance covered upstream in 8 hrs 48 min = Distance covered downstream in 4 hrs.
[U*8*48/60] = [V*4] [BECAUSE 1 MINUTE=60SECONDS]
[U*8*4/5] = [4V]
[U*44/5] = [4V]
44/5 U = 4V
THEN, USE THE FORMULA-----If the speed of the boat in still water is U km/hr and the stream of the boat is V km/hr then.
speed downstream = (u+v)km/hr
speed up stream = (u+v)km/hr
so, our U= 44/5 COME AND V= 4 COME
NOW, [U+V]/[U-V]
[44/5+4] / [44/5-4]
[44+20] / [44-20]
64/24,
8/3,
8:3 ANS
Manojit said:
1 decade ago
Thanks Bindu.
Nitin Gusain said:
1 decade ago
Take it as in easy way
x= upstream speed
y= downstream speed
now we know that
upstream speed(x) = boat speed - stream speed
downstream speed(y) = boat speed + stream speed
so, x+y = 2*boat speed
x-y = 2*stream speed
so ratio of boat speed to stream speed is = (x+y)/(x-y)
x= upstream speed
y= downstream speed
now we know that
upstream speed(x) = boat speed - stream speed
downstream speed(y) = boat speed + stream speed
so, x+y = 2*boat speed
x-y = 2*stream speed
so ratio of boat speed to stream speed is = (x+y)/(x-y)
Aag said:
1 decade ago
I got 13:3 please help I'm not getting 8:3.
Srinu said:
1 decade ago
I didn't understand how 8*4/5 will get.
Anbu said:
1 decade ago
Bindu your answer is suitable for all this type of problems?
Anbu said:
1 decade ago
@Bindu.
Your answer is suitable for all this type of problems?
Your answer is suitable for all this type of problems?
Hema said:
1 decade ago
I'm not understand this step 16/5*1/2 please help me.
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).
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