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Maths problem

Maths problem

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Hi there!
I have a math problem I found on the internet (or maybe it's more physics, I dunno). I have a solution, but as nobody put up the correct answer, I don't know if I have it right.
So if anybody has the time and interest, here's the question, thanks for posting your answers 😉

The Harvard bridge and the Longfellow bridge cross the Charles River in a distance of 1 mile from each other. A boat team is rowing upstream from the longfellow bridge. As the boat passes the Harvard bridge, the helmsman's hat falls into the river. After ten minutes he notices and turns around the boat immediately, letting the team row downstream with the same amount of beats per minute. When they reach the hat, they are at the Longfellow bridge again.

What speed is the river flowing at?

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Post it in the "Posers & Puzzles" Forum here. There are myriad clever guys there who'd like nothing (... well... almost nothing) better than giving you the solution.

Cheers



🙂

1 edit
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Three million Km/sec


Damn. wrong k constant! I'll think again!

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The speed of the flow is 3 miles per hours.

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Originally posted by angie88
Hi there!
I have a math problem I found on the internet (or maybe it's more physics, I dunno). I have a solution, but as nobody put up the correct answer, I don't know if I have it right.
So if anybody has the time and interest, here's the question, thanks for posting your answers 😉

The Harvard bridge and the Longfellow bridge cross the Charles River i ...[text shortened]... ach the hat, they are at the Longfellow bridge again.

What speed is the river flowing at?
The river is (I think) flowing at 60 devided by10+ (the time it took to reach the hat)miles per hour.
I think the equation is incomplete. We need to know when the boat reached the hat.

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No,
if we assume the speed of the river flow is X miles per min
the speed of the boat is y miles per min.
Then 1/X=10+[10(y-x)+]/(y+x)
and if we solve this equation we get x=1/20 miles per min.

Edit: you probably came up with something like this equation but did not relise the y's will divide out.

1 edit
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Originally posted by h9i9j9
No,
if we assume the speed of the river flow is X miles per min
the speed of the boat is y miles per min.
Then 1/X=10+[10(y-x)+]/(y+x)
and if we solve this equation we get x=1/20 miles per min.

Edit: you probably came up with something like this equation but did not relise the y's will divide out.
I expect you're right. Too noisy to concentrate here!