Cool Math/Logic Problem

[pshreck]

Yeah, that is significantly different than the original posted question, which implied something mathematically impossible without some sort of trick.

[daryn]

</font><blockquote><font class="small">In risposta di:</font><hr />
Yeah, that is significantly different than the original posted question, which implied something mathematically impossible without some sort of trick.

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in conclusion, daryn again was first with the correct answer!

[Bill Murphy]

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[pshreck]

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Yeah, that is significantly different than the original posted question, which implied something mathematically impossible without some sort of trick.

[/ QUOTE ]

in conclusion, daryn again was first with the correct answer!

[/ QUOTE ]

Daryn, some kid like 10 years ago figured out an error on a math problem on the SAT's, and actually refused to answer it and wrote down the error on the form, on his way to scoring a perfect 800 on math.

That was you right?

[daryn]

wow that is almost so correct it's scary [img]/images/graemlins/shocked.gif[/img]

[Skjonne]

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Alright, here it is(I knew I should've just copied it word for word).

The key is, when the ferries first pass each other, what's the total distance traveled by each? The width of the river, of course. Now, when they pass again, what's the total distance traveled? Three times the width, right? So, assuming constant speeds, the ferry that left Pier A has now traveled 720 yds x 3 = 2160 yds. And as its now 400 yds from Pier B the width of the river is 1760 yds or a mile.

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[img]/images/graemlins/smile.gif[/img] That was simple. I did it the math'ish way:

Ferry A travels with a speed of A. Ferry B with a speed of B. After T1 hours they meet for the first time, therefore

A*T1 = 720 and
B*T1 = L-720, L beeing the lenght of the river.

After their fist meeting they travel for T2 hours and meet again. Therfore

A*T2 = (L-720) + 400 and
B*T2 = 720 + (L-400)

Elimínating T1 from the first set of equations gives
A/B = (720)/(L-720)

Elimínating T2 from the second set of equations gives
A/B = (L-320)/(L+320)

Now we can eliminate A/B:
(720)/(L-720)=(L-320)/(L+320)

Solving this for L gives

L=1760

[jakethebake]

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Cool Math/Logic Problem

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What kind of geek thinks math problems are "cool"?

[pudley4]

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Yeah, that is significantly different than the original posted question, which implied something mathematically impossible without some sort of trick.

[/ QUOTE ]

in conclusion, daryn again was first with the correct answer!

[/ QUOTE ]

Daryn, some kid like 10 years ago figured out an error on a math problem on the SAT's, and actually refused to answer it and wrote down the error on the form, on his way to scoring a perfect 800 on math.

That was you right?

[/ QUOTE ]

Here's the question:

Circle A has a circumference of 4pi. Circle B has a circumference of 1pi.

Circle B sits on top of Circle A, and rolls clockwise one time around the entire circumference of Circle A, stopping when it gets back to the top of Circle A.

How many times does Circle B make a complete revolution of itself?

(If anyone needs one, I'll try to put up a picture)