Question

(iv) A steamer goes downstream and covers the distance between two ports in 3 h.
It covers the same distance in 5 h, when it goes upstream. If the stream flows at
4 km/h, then what is the speed of steamer upstream?



The answer which will be written elaborately and written step by step, I will surely mark that answer as brainliest...
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Answer 1

Answer:

let us consider that the speed of of the steamer is x km/h,

and distance between 2 ports is d km.

therefore, for the case of downstream, the total speed of steamer should be as stated below:

x + 3 (because the flow of stream is 3 km/h which adds up with the steamers' speed in the case of down stream)

in the case of upstream, the total speed of steamer should be as show below:

x-3 (because the flow of the stream is against the steamer which slows down the steamer.)

now, Speed=distance/time

for the downstream, x+3 = d/3,

therefore, d=3*(x+3)----equation_(1)

now, for the upstream, x-3 = d/5,

therefore, d=5*(x-3)

from equation_(1) where d=3*(x+3),

5*(x-3)=3*(x+3)

5x-15=3x+9

5x-3x=9+15

2x=24

x=12 km/h

speed of the steamer is 12 km/h

now the speed of steamer in upstream= x-3 = 12-3 = 9 km/h

∴, the speed of steamer upstream is 9 km/h.  

Hope this helps!