In an exceptionally long corridor in the Space Station,
there are one thousand windows along one wall.
Coincidentally, there are exactly one thousand Men in the station.
Astronaut boss orders the first Man to open the blinds on every window.
Then, he orders the second Man to close the blinds on every second window.
Then the third Man is told to go to every third window,
and close the blinds if they are open, and open the blinds if they are closed.
The fourth Man does this for every fourth window, and so on.
After all 1000 Men complete the process, how many blinds are open?
this is hard i know but i couldnt figure out the answer. have some fun with it and please try to figure it out :D
2007-03-06 10:44:11 · 8 answers · asked by Squirrel 1 in Entertainment & Music ➔ Jokes & Riddles
OK, I suck at math but let me try:
The first window remains open. Since the second man closes the blinds on every second window, the third one will have to close the blinds on every third one, as they will all be open. Since we know the first man opened the blinds first, we know that the thousandth man had to close them all, except the first. The blinds will all be closed with the exception of the first, and thus only 1 set of blinds will remain open.
I KNOW there is some mathematical equation for this, but, like I said, I suck at math. =)
2007-03-06 11:04:56 · answer #1 · answered by Me, Thrice-Baked 5 · 0⤊ 0⤋
All the ones which are perfect squares....(ex: 1,4,9,16,25,36,49 etc...) so 31 windows are open...(31x31 = 961)
The nth blind is opened or closed by astronaut number k precisely when k divides n. So if astronaut k changes locker n, so does astronaut n/k. They cancel each other out. This always holds unless astronauts k and n/k are precisely the same person. That is, k = n/k. The lockers that are exact squares will remain open. These are blinds 1, 4, 9, 16, 25, etc. How many of these are there in a 1,000? You can go all the way up to 31Ã31 = 961, hence there are 31 lockers open.
2007-03-06 19:55:33 · answer #2 · answered by Anonymous · 4⤊ 0⤋
Only 1 blind is remaining open.. the first blind. The other men closed the blinds
2007-03-06 18:55:50 · answer #3 · answered by quiescent_soul 2 · 0⤊ 0⤋
only the first window
2007-03-10 14:22:09 · answer #4 · answered by donkey hotay 3 · 0⤊ 0⤋
I think only one, the first one
2007-03-06 19:10:05 · answer #5 · answered by rose 1 · 0⤊ 0⤋
one
2007-03-06 19:49:45 · answer #6 · answered by Anonymous · 0⤊ 0⤋
500? it would still be every other.
2007-03-06 18:51:05 · answer #7 · answered by i'm a rock star 2 · 0⤊ 0⤋
I DONT KNOW!!!! thats hard..............
2007-03-06 18:48:46 · answer #8 · answered by Mudgy4 2 · 0⤊ 0⤋