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## #1 2012-12-29 21:34:38

scientia
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### Mandy and Sandy

This is my adaptation of a math problem I came across elsewhere on the Internet.

Mandy has just done her shopping at the shopping center; now she is hungry and wants to go to the restaurant for lunch. Sandy has just had something to eat at the restaurant; now she wants to go to the shopping center and buy some clothes. A park is situated between the shopping center and the restaurant. Mandy sets off from the shopping center at 2:00pm, walks through the park, and arrives at the restaurant at 2:30pm. Sandy leaves the restaurant at 1:43pm, takes the same route through the park (but in the opposite direction) and gets to the shopping center at 2:23pm. Both girls enter the park at the same time and Mandy leaves the park 4 minutes earlier than Sandy.

First question (easy): Find the time (to the nearest minute) at which both girls meet.

Last edited by scientia (2012-12-30 02:48:24)

## #2 2012-12-30 01:21:40

bobbym

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### Re: Mandy and Sandy

Hi;

In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.

## #3 2012-12-30 01:51:45

scientia
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### Re: Mandy and Sandy

Correct.

Next question (harder): At what time did both girls enter the park?

Last edited by scientia (2012-12-30 02:47:52)

## #4 2012-12-30 02:13:40

bobbym

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### Re: Mandy and Sandy

Hi;

In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.

scientia
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## #6 2012-12-30 02:44:00

bobbym

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### Re: Mandy and Sandy

Hi;

In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.

## #7 2012-12-30 03:09:41

scientia
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### Re: Mandy and Sandy

I'm not sure you you did there. Maybe part of my first post isn't very clear, so I'll try and explain.

The park has two ends, A and B, where A is the end closer to the shopping mall and B the end closer to the restaurant. The route taken by Mandy is: shopping mall → A → park → B → restaurant. Sandy's route is the reverse: restaurant → B → park → A → shopping mall. Thus when I say that the girls enter the park at the same time, I mean that Mandy reaches point A and Sandy reaches point B simultaneously.

Last edited by scientia (2012-12-30 03:11:47)

## #8 2012-12-30 03:25:18

bobbym

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### Re: Mandy and Sandy

Hi;

In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.

## #9 2012-12-30 03:45:40

anonimnystefy
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### Re: Mandy and Sandy

Hi bobbym

I think that should be hidden...

The limit operator is just an excuse for doing something you know you can't.
“It's the subject that nobody knows anything about that we can all talk about!” ― Richard Feynman
“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment

## #10 2012-12-30 03:47:27

scientia
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### Re: Mandy and Sandy

Last edited by scientia (2012-12-30 04:37:50)

## #11 2012-12-30 04:19:39

bobbym

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### Re: Mandy and Sandy

Hi;

Yes, that was a dilly.

In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.

scientia
Full Member

Offline

## #13 2012-12-30 04:41:01

bobbym

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### Re: Mandy and Sandy

Hi;

A false step on the park size formula. Very good problem.

In mathematics, you don't understand things. You just get used to them.
I have the result, but I do not yet know how to get it.
All physicists, and a good many quite respectable mathematicians are contemptuous about proof.