Aptitude - Boats and Streams - Discussion
Discussion Forum : Boats and Streams - General Questions (Q.No. 15)
15.
A man rows to a place 48 km distant and come back in 14 hours. He finds that he can row 4 km with the stream in the same time as 3 km against the stream. The rate of the stream is:
Answer: Option
Explanation:
Suppose he move 4 km downstream in x hours. Then,
| Speed downstream = |  |
4 |  |
km/hr. |
| x |
| Speed upstream = | |
3 | |
km/hr. |
| x |
 |
48 | + | 48 | = 14 or x = | 1 | . |
| (4/x) | (3/x) | 2 |
So, Speed downstream = 8 km/hr, Speed upstream = 6 km/hr.
| Rate of the stream = | 1 | (8 - 6) km/hr = 1 km/hr. |
| 2 |
Discussion:
48 comments Page 3 of 5.
Subhrasubha priyadarsini said:
8 years ago
4/x+y=3/x-y,
4x-4y=3x+,
x=7y -----> eq1
48/x+y +48/x-y =14,
48/8y+48/6y=14,
14/y=14,
y=1,
Now x=7.
4x-4y=3x+,
x=7y -----> eq1
48/x+y +48/x-y =14,
48/8y+48/6y=14,
14/y=14,
y=1,
Now x=7.
Shanur Rahman said:
8 years ago
Suppose it took him x hrs to go downstream, then it will take him 14-x upstream. Therefore x/ (14-x) = 3/4.
There you go.
There you go.
Priya said:
8 years ago
Distance=48 km in 14 hours.
rate of stream = x.
downstream=4 km (with the water).
Upstream =3 km(against the water).
Rate of the stream =1/2(4-3)=1/2.
Therefore x=1/2.
Then,4/1/2 =4 * 2 = 8.
Then,3/1/2 = 3 * 2 = 6.
So,1/2(8-6) = 1/2(2)
Answer is 1.
rate of stream = x.
downstream=4 km (with the water).
Upstream =3 km(against the water).
Rate of the stream =1/2(4-3)=1/2.
Therefore x=1/2.
Then,4/1/2 =4 * 2 = 8.
Then,3/1/2 = 3 * 2 = 6.
So,1/2(8-6) = 1/2(2)
Answer is 1.
Pouvanam said:
9 years ago
How do you find the value of x?
Padma said:
1 decade ago
I am not able to understand why x=1/2 and,
Speed downstream = (4/x).
Speed upstream = (3/x).
Can anyone clear my doubt?
Speed downstream = (4/x).
Speed upstream = (3/x).
Can anyone clear my doubt?
Ram said:
1 decade ago
I'm also having this doubt. Anybody help me.
Manish said:
1 decade ago
We know that x=1/2, put this value in speed downstream= (4/x) then we get speed down stream=8km/h similarly we get speed upstream.
Manish said:
1 decade ago
Speed of down stream is always greater than upstream because in down stream the gravitational force enhence some speed of the stream.
Rohit said:
1 decade ago
Is there any other solotion without assuming the x ?
Anik said:
1 decade ago
@Rohit
It is impossible without assuming x i.e algebraic method, learn more on this.
It is impossible without assuming x i.e algebraic method, learn more on this.
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers