Aptitude - Boats and Streams - Discussion
Discussion Forum : Boats and Streams - General Questions (Q.No. 9)
9.
A man can row at 5 kmph in still water. If the velocity of current is 1 kmph and it takes him 1 hour to row to a place and come back, how far is the place?
Answer: Option
Explanation:
Speed downstream = (5 + 1) kmph = 6 kmph.
Speed upstream = (5 - 1) kmph = 4 kmph.
Let the required distance be x km.
| Then, | x | + | x | = 1 |
| 6 | 4 |
2x + 3x = 12
5x = 12
x = 2.4 km.
Discussion:
21 comments Page 2 of 3.
Ayush said:
9 years ago
Easy way to solve this type of question is followed by a simple formula.
i.e
D = T[sb square - ss square]/2*sb.
sb means the speed of a boat.
ss means the speed of a stream.
i.e
D = T[sb square - ss square]/2*sb.
sb means the speed of a boat.
ss means the speed of a stream.
Utteya Pal said:
10 years ago
Easiest way to do this kind of problems:
{z(x^2-y^2)}/2x.
Here z= time taken to cover the both distance.
x = speed in still water.
y = speed of current.
{z(x^2-y^2)}/2x.
Here z= time taken to cover the both distance.
x = speed in still water.
y = speed of current.
Sam said:
1 decade ago
(4x+6x)/(6*4) = 1.
4x+6x = 24.
10x = 24.
x = 24/10.
x = 2.4.
I hope You are all understand.
4x+6x = 24.
10x = 24.
x = 24/10.
x = 2.4.
I hope You are all understand.
(1)
Ashwin Hingole said:
1 decade ago
I think answer to how far is the place should be 1.2 km. And answer to how much distance man has covered should be 2.4 km. He goes and comes back. Suggestions please.
Kandarp Singh said:
1 decade ago
12 is the lcm of 4 and 6 and that expression solving is correct.
x/6 + x/4 = 1.
(4x+6x)/(6*4) = 1.
(2x+2x)/(3*4) = 1.
2x+3x = 12.
x/6 + x/4 = 1.
(4x+6x)/(6*4) = 1.
(2x+2x)/(3*4) = 1.
2x+3x = 12.
Shantanu datta said:
1 decade ago
From where is this 12 coming from?
2x+3x=6 after the first step.
2x+3x=6 after the first step.
Rakesh KIIT said:
1 decade ago
Average Speed during toatal journey=2(6)(4)/(6+4)
=4.8 kmph
so, Total distance coverd during the Journey=Time* Average speed
=1*4.8
=4.8km
so, How far is the place = 4.8/2
= 2.4 km
Because man goes and come back.
=4.8 kmph
so, Total distance coverd during the Journey=Time* Average speed
=1*4.8
=4.8km
so, How far is the place = 4.8/2
= 2.4 km
Because man goes and come back.
Dts said:
1 decade ago
Here we take lcm only.
Bhima God said:
1 decade ago
Mul of 6 and 4 should be 24 right?...how that 12 comes?
Sasikumar said:
1 decade ago
Speed downstream = (5 + 1) kmph = 6 kmph.
Speed upstream = (5 - 1) kmph = 4 kmph.
average speed=2(6)(4)/(6+4)
Speed upstream = (5 - 1) kmph = 4 kmph.
average speed=2(6)(4)/(6+4)
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