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 6 of 8.
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.
Kush said:
1 decade ago
hi ! @Vijaya.
In question, it will be already provided the keyword like upstream or downstream and With stream or Against Stream.
In question, it will be already provided the keyword like upstream or downstream and With stream or Against Stream.
Vijaya said:
1 decade ago
Hi. Guyz. I have one doubt. ? how we know. The given question is upstream or downstream. I can't understand that. If you don't mind can you please tell me that.
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.
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.
Atuljain said:
1 decade ago
Downstream = speed of the man + speed of the stream.
15 = x+2.5.
x = 12.5.
Upstream = speed of the man - speed of the stream.
x = 12.5-2.5.
x = 10.
15 = x+2.5.
x = 12.5.
Upstream = speed of the man - speed of the stream.
x = 12.5-2.5.
x = 10.
Karthik said:
1 decade ago
The actual speed is 12.5. Due to downstream it becomes 15 (adding 2.5) and due to upstream it becomes 10 (subtracting 2.5). Simple no confusions.
Sapna said:
1 decade ago
Solve acc to formula,
We have
Current=1/2(a-b).
So,
2.5=1/2(15-b).
2.5*2=15-b.
b=10km/hr.
We have
Current=1/2(a-b).
So,
2.5=1/2(15-b).
2.5*2=15-b.
b=10km/hr.
Raj said:
1 decade ago
The speed of man is 15 including the speed of current.
Actual speed of man is 12. 5,
And now against the current 12. 5-2. 5 (speed of current) =10.
Actual speed of man is 12. 5,
And now against the current 12. 5-2. 5 (speed of current) =10.
Prasad said:
1 decade ago
How do we know the man is traveling in boat with out mention in the question?
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