another brain teaser for the math inclined

lotus776 · #1 11-15-2005, 11:23 PM

1000 lockers at WENUMBEREM HS are displayed in one long row and are labeled from 1 to 1000. In addition, 1000 students are lined up in a row at locker number 1. The first student runs and opens every locker. The third student runs through and CHANGES every third locker; that is, if it is open, he closes it; if it is closed, he opens it. The fourth student runs through and CHANGES every fourth locker. This process continues until the 1000th student runs through and changes the 1000th locker.
1) At the end of this process, which numbered lockers are left open?

2) What is the pattern of numbers in (1)? BE VERY SPECIFIC!

3) what is the reasoning for this pattern? EXPLAIN IN DETAIL!

good luck

RJT · #2 11-15-2005, 11:37 PM

I don't have my mind on this problem right now - so, if I missed something, then nevermind. Did you forget to say what the second kid does or is that part of the problem? Quick glance is it seems we need this info.

slavic · #3 11-16-2005, 12:55 AM

Never mind I dodn't realise it was your homework

Try working smaller examples you'll figure it out.

jason_t · #4 11-16-2005, 01:03 AM

You'll never learn if you don't do your own homework.

lotus776 · #5 11-16-2005, 02:21 AM

why is everyone so concerned with teaching me a lesson in doing my own homework?

this is NOT homework, I do these probs out of a book daily and this one stumped me...not like any of that matters

if you have an answer then answer, if not just don't say anything

jason_t · #6 11-16-2005, 02:27 AM

It's because this one is fairly easy. [img]/images/graemlins/shocked.gif[/img]

lotus776 · #7 11-16-2005, 02:31 AM

easy is subjective

lotus776 · #8 11-16-2005, 02:37 AM

and the simplicity of the problem is irrelavent. I'm asking for help and if you're not willing to give any then I will wait until someone will.
Now, do you have any useful info for me?

housenuts · #9 11-16-2005, 02:38 AM

so does the 2nd student sit there with his thumb in his bum. ie. he's the only student that does nothing?

jason_t · #10 11-16-2005, 03:20 AM

[ QUOTE ]
and the simplicity of the problem is irrelavent. I'm asking for help and if you're not willing to give any then I will wait until someone will.
Now, do you have any useful info for me?

[/ QUOTE ]

You've already been told to work small examples. Why are you being so, I don't know, demanding if this isn't a homework assignment.