Math Is Fun Forum

Dharshi

Member

Registered: 2006-10-31

Posts: 56

Upstream problems

A steamer goes downstream and covers the distance between two points in 4 hours while it covers the same distance upsteam in 5 hours. If the speed of the stream is 2 km/hr, then the speed of the steamer is.....

Can you solve it in steps and tell me the answer?:/

Last edited by Dharshi (2008-04-06 19:44:23)

mathsyperson

Moderator

Registered: 2005-06-22

Posts: 4,900

Re: Upstream problems

You can get two simultaneous equations in two variables out of this (which you can then solve).

Downstream: Call the distance that it travels in the 4 hours d, and its speed v.
Due to the river, it is effectively travelling at v+2 km/h. Hence, using distance = speed x time, we get:

d = 4(v+2)

Upstream: Using a similar argument, we find that d = 5(v-2)

Solve the two bolded equations simultaneously and you'll get your answer.

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Why did the vector cross the road?
It wanted to be normal.

Dharshi

Member

Registered: 2006-10-31

Posts: 56

Re: Upstream problems

yeah!! i got it. I need one more help. I want to know about rational numbers, like who found it.Can any one help me on this?