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:
8.5 km/hr
9 km/hr
10 km/hr
12.5 km/hr
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 3 of 8.

Mahima said:   8 years ago
Thank you @Balaji. You explained it very clearly.

Deepika said:   8 years ago
Sir, I have one doubt.

Given downstream speed (i.e speed of boat with stream)is 15 km/hr .asked ..upstream speed is( boat speed(u)- stream speed(v)).

Here to find the boat speed we use boat speed= downstream speed - stream speed.what should we do if upstream speed( speed of boat against stream) is given in the question.

Should we do like this, boat speed=upstream speed+ stream speed.

Akash r said:   8 years ago
Thank you @Balaji.

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.

Abc said:   7 years ago
Not getting. Please, someone, help me to get it.

HARI said:   7 years ago
Speed in current =15,
Current speed =2.5,
Upstream =15-2.5=12.5,
Downstream =15+2.5=17.5.

SHRIPAD said:   7 years ago
Thanks @Atuljain.

Sijohn joy said:   7 years ago
d=15 y=2.5.
u=?.

15-u/2=2.5,
15-u=5,
u=15-5=10.

Anusha said:   5 years ago
@Sapna.

Very accurate explanation. Thanks.

Yogi said:   7 years ago
I am not understanding this. Please explain me.


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