Suppose you’re in a hallway with 100 closed lockers against the wall.
You start by opening every locker. Then you go back and close every second locker. Then you go to every third locker and open it if it’s closed, or close it if it’s open. Let’s call this action ‘toggling’ a locker. Continue ‘toggling’ every nth locker on pass no n (e.g. ‘toggling’ every 26th locker on pass 26).
My question is, after 100 passes, where you ‘toggle’ only locker #100, how many lockers are open?
Answer in the comments area below, with some reasoning or an explanation please! Good luck!
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i dont know
dont understand the teaser….
This is hard, lets say 1 million.
I worked this out using a spreadsheet.There were 10 lockers open at the end ,they were 1,4,9,16,25,36,49,64,81,100.
the answer is 10!!!!
I did it on the link that you put on the website, and the answer was 10. It was easy to do on the website, it would be really hard to do it on paper!
18 closed
82 open
Well done to those of you who tried this, either manually or using technology!
Ashton thinks that is “easy on the website but hard on paper”.
In class we will try it using only the power of our brains - to think the problem through and arrive at an elegant mathematical solution that requires neither technology nor reams of paper!!!
I have no idea how to do ths
Me and Kaleigh worked this out in S.E and the answer is “10″
It was pretty easy on the Lockers website but when we tried it on paper it was Very Hard. =)
We are still working on “Is the number 1 a prime number ?”