Ok, my son has this math problem and we can not figure it out. LOL.
My mind is blank.
Here is the problem:
On graduation day, 200 seniors lined up outside the school. As they entered the school, they passed their lockers that were numbered from 1 to 200. The first student opened all of the lockers. The second student closed every second locker. The third student changed the position of every third locker. (If the locker was open, the student closed it; if the locker was closed, the student opened it.) The fourth student changed the position of every fourth locker, and so on until the last student entered the school. Which lockers remained open after all 200 students entered the school?
All of them.
The last student through was an illegal immigrant and after all the free handouts he and his family have taken from honest taxpayers and hard working citizens, felt thet everything was free to him and helped himself to all the other student's lunch money that they had in their lockers.
What was so hard about that?
LOL. So your saying all of them (closed)? If so thats what I was thinking but math was not my best subject. LOL
A school has 1,000 students and 1,000 lockers, all in a row. They all start out closed. The first student walks down the line and opens each one. The second student closes the even numbered lockers. The third student approaches every third locker and changes its state. If it was open he closes it; if it was closed he opens it. The fourth student does the same to every fourth locker, and so on through 1,000 students. To illustrate, the tenth locker is opened by the first student, closed by the second, reopened by the fifth, and then closed by the tenth. All the other students pass by the tenth locker, so it winds up being closed. How many lockers are open?
A~The nth locker is opened or closed by student number k precisely when k divides n. So if student k changes locker n, so does student n/k. They cancel each other out. This always holds unless students 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 lockers 1, 4, 9, 16, 25, etc. How many of these are there in a row of 1,000? You can go all the way up to 31×31 = 961, hence there are 31 lockers open.
Damned if I know
http://www.eklhad.net/funmath.html
C.T. :wink:
Ok Darn, back to drinking beer.
I'm being called out to do a 1 1/2 of the diving board by my son and his friends, wish me luck be right back.
So is the answer (all of them closed)?
AHHHHH....Tuesday?
So is the answer (all of them closed)?
14x14=196. So answer is 14.
n=200, k=n/k, 14x14=196, k=14... 14 lockers open.
I thinks, I was never into geography.
Ok Darn, back to drinking beer.
I'm being called out to do a 1 1/2 of the diving board by my son and his friends, wish me luck be right back.
So is the answer (all of them closed)?
Well???
My Son could answer the math qusetion, but not I
jm
It's a trick question, of sorts. The only one that will still be open is one. Every prime number will be opened by 1 and closed by it's own number. Every non prime number will have an equal number of opens and close because a number, for example 56, will always have couplets that when mulitplied make that number. 1 x 56, 2 x 28, 4 x 14, 7 x 8. 1 is the only number that would not have at least an open and close. One is the loneliest number.
I like that. I believe you are right Good thinking
John M
Ok Darn, back to drinking beer.
I'm being called out to do a 1 1/2 of the diving board by my son and his friends, wish me luck be right back.
So is the answer (all of them closed)?
SO DO THE FLIP BUT REMEMBER THIS, HOW MANY DOORS ON YOUR HOUSE ARE OPEN
and if you used beer for this question you would have figured it out in no time
Posting Permissions
Reply With Quote