Aptitude - Boats and Streams - Discussion
Discussion Forum : Boats and Streams - General Questions (Q.No. 2)
2.
A man's speed with the current is 15 km/hr and the speed of the current is 2.5 km/hr. The man's speed against the current is:
Answer: Option
Explanation:
Man's rate in still water = (15 - 2.5) km/hr = 12.5 km/hr.
Man's rate against the current = (12.5 - 2.5) km/hr = 10 km/hr.
Discussion:
72 comments Page 2 of 8.
Sravya said:
1 decade ago
Let speed of man be 'a'
speed of current be 'b'
given man's speed with current (a+b)=15 km\hr nd speed of current is 2.5
substitute in abv eqn (a+2.5)=15
a=15-2.5
a=12.5
but problem is abt finding man's speed against current i,e
(a-b)=12.5-2.5
=10
speed of current be 'b'
given man's speed with current (a+b)=15 km\hr nd speed of current is 2.5
substitute in abv eqn (a+2.5)=15
a=15-2.5
a=12.5
but problem is abt finding man's speed against current i,e
(a-b)=12.5-2.5
=10
Ganga said:
6 years ago
Man's speed with current=15.
i.e., man's speed + current speed =15 km,
Now we want man's speed alone, so;
Man's speed = 15-currrent speed.
i.e.,man's speed = 15-2.5 = 12.5.
Now calculate Man's speed against the current =>Man's speed - Current speed = 12.5 - 2.5 = 10 km/hr.
i.e., man's speed + current speed =15 km,
Now we want man's speed alone, so;
Man's speed = 15-currrent speed.
i.e.,man's speed = 15-2.5 = 12.5.
Now calculate Man's speed against the current =>Man's speed - Current speed = 12.5 - 2.5 = 10 km/hr.
(3)
Arun.D said:
1 decade ago
Man's speed with the current = 15 km/hr.
Speed of the current = 2.5 km/hr.
Man's speed against the current=?
Downstream = (u+v)km/hr.
u+v = 15.
v = 2.5.
u+2.5 = 15.
u = 15-2.5.
u = 12.5km/hr.
Upstream = (u-v)km/hr.
= (12.5-2.5)km/hr.
= 10km/hr.
Speed of the current = 2.5 km/hr.
Man's speed against the current=?
Downstream = (u+v)km/hr.
u+v = 15.
v = 2.5.
u+2.5 = 15.
u = 15-2.5.
u = 12.5km/hr.
Upstream = (u-v)km/hr.
= (12.5-2.5)km/hr.
= 10km/hr.
Ankita Chandra said:
7 years ago
Man's speed + speed of current = 15,
Man's speed + 2.5 = 15,
Man's speed = 15 - 2.5 = 12.5,
Man's rate against the current i.e. difference between their speed ( u-v).
Man's speed - speed of current.
= 12.5 - 2.5,
= 10.
Man's speed + 2.5 = 15,
Man's speed = 15 - 2.5 = 12.5,
Man's rate against the current i.e. difference between their speed ( u-v).
Man's speed - speed of current.
= 12.5 - 2.5,
= 10.
(1)
Ramakrishna said:
1 decade ago
Given that mans speed with current means mans speed+current = 15, So here current is given from which we get actual speed of man is 12.5km/hr, Then he asked against the current so the answer will be 12.5 - 2.5=10km/hr.
Peauts said:
7 years ago
You are right @Deepika
a=u+v(speed of downstream/speed of man with the stream(i.e)he is going along with the stream)
u=a-v (speed of the man alone)=12.5
b=u-v
if b is given:
put b=u-v
So, u=b+v.
a=u+v(speed of downstream/speed of man with the stream(i.e)he is going along with the stream)
u=a-v (speed of the man alone)=12.5
b=u-v
if b is given:
put b=u-v
So, u=b+v.
Shyam said:
8 years ago
@Vishal.
15 is the speed of the man "with" speed of current i.e., 15 is the speed of man in downstream.
That means M + S = 15; S = 2.5.
Finally, man's speed =15-2.5 = 12.5.
15 is the speed of the man "with" speed of current i.e., 15 is the speed of man in downstream.
That means M + S = 15; S = 2.5.
Finally, man's speed =15-2.5 = 12.5.
Bhavani said:
1 decade ago
With stream = a+b(speed of d object in still water +speed of d stream) => Down stream.
Against stream = a-b(speed of d object in d still water - speed of d stream) => up stream.
Against stream = a-b(speed of d object in d still water - speed of d stream) => up stream.
Arun said:
4 years ago
Hey guys.
If they said the man speed is ..the answer is 12.5...but;
The man speed with the current.
So the 15 km/hr have ( man speed + Current speed).
So the answer is 10km/hr.
If they said the man speed is ..the answer is 12.5...but;
The man speed with the current.
So the 15 km/hr have ( man speed + Current speed).
So the answer is 10km/hr.
(3)
Anup gupta said:
1 decade ago
No upstream speed can be any one less than 12.5. I. E. Against the stream. Question is not that what will be the speed if he will move against the stream at 2.5.
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