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### Word Problem Hints

```
Date: 3/12/96 at 22:3:37
From: John Reichel
Subject: help

I have two questions I could use some help on.

1)  There are 1000 lockers numbered 1 - 1000.  Suppose you open
all of the lockers, then close every other locker.  Then, for
every third locker, you close each opened locker and open each
closed locker.  You follow the same pattern for every fourth
locker, every fifth locker, and so on up to every thousandth
locker.  Which locker doors will be open when the process is
complete?

2)  A certain substance doubles in volume every minute.  At 9:00
a.m. a small amount is placed in a container and at 10:00 a.m. the
container is just full.  At what time was the container on quarter
full?

appreciate it.

John Reichel
```

```
Date: 3/14/96 at 18:24:45
From: Doctor Jodi
Subject: Re: help

Hi John!

Our office is overflowing with patients at the moment, so let me
just try to put a bandaid on these problems for you...

Thinking about the influence of FACTORS in the first problem might
help.

I imagine the row of lockers as a long line of off/on switches.

Let me give you a hint on the second question.  If the substance
doubles every minute, when was the container half full?  Can you
use the same sort of approach to find out when it was a quarter
full?

know how the problems are going, or to ask for more help when you
need it.

-Doctor Jodi,  The Math Forum

```
Associated Topics:
High School Discrete Mathematics

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