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:
74 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:
7 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.
Dr saim bhat said:
4 weeks ago
The speed of the boat is always mid-value.
The speed of the stream is the difference between upstream and downstream.
Boat speed upstream+downstream divided by 2.
The speed of the stream = upstream-downstream divided by 2.
The speed of the stream is the difference between upstream and downstream.
Boat speed upstream+downstream divided by 2.
The speed of the stream = upstream-downstream divided by 2.
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:
8 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)
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