test your intelligence 3
time passes fast when u r slacking at home, but now that i'm working, i realised time passes faster when u work.
anyway, it's tuesday again! time to test ur intelligence, but sad to say no one has yet to solve for last week problem.
This week's problem shall be slightly easier:
A high school has this ritual on the last day of school: The students go into the hall and stand by their closed lockers.
At the first blow of a whistle, the students open every locker. At the second whistle, the students close every second locker (lockers 2, 4, 6, etc., are slammed shut). At the third whistle, the students toggle every third locker. To "toggle" means to close it if it's open, and to open it if it's closed. They toggle 3, 6, 9, etc.
At whistle four, they toggle every fourth locker. At whistle five, they toggle every fifth locker, and so on.
Let's make things easy and say it's a small school with only 100 lockers. At the one hundredth whistle, the student standing next to locker 100 toggles his locker.
How many and which are the lockers are then open?
anyway, it's tuesday again! time to test ur intelligence, but sad to say no one has yet to solve for last week problem.
This week's problem shall be slightly easier:
A high school has this ritual on the last day of school: The students go into the hall and stand by their closed lockers.
At the first blow of a whistle, the students open every locker. At the second whistle, the students close every second locker (lockers 2, 4, 6, etc., are slammed shut). At the third whistle, the students toggle every third locker. To "toggle" means to close it if it's open, and to open it if it's closed. They toggle 3, 6, 9, etc.
At whistle four, they toggle every fourth locker. At whistle five, they toggle every fifth locker, and so on.
Let's make things easy and say it's a small school with only 100 lockers. At the one hundredth whistle, the student standing next to locker 100 toggles his locker.
How many and which are the lockers are then open?
posted by cLeMeNt at 6:50 PM
3 Comments:
10? 1, 4, 9, 16, 25, 36, 49, 64, 81, 100.
i shall conclude it's correct haha. bcos these square numbers, are the only numbers that have odd no of factors. odd no of factors cause it to be eventually open since we started as open. the no of factors determine the result of the lockers.
wah gekleng.. clever sia. know how to explain people's ans.
ya it's correct.
but the odd no of factors cause it to be eventually open since we started as CLOSED. (u made a typo error)
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