Another light switch riddle
posted by Andyy
- February 17 2009 01:29:35 PM
There are a hundred light switches in a row, all in the off position. Vanna White goes by and flips every one. Then she flips every other one. Next she flips every third light switch. She continues with every 4th, 5th, 6th, etc, until finally, she flips "every 100th" light switch (of course there is only one).
Which light switches are in the "on" position?
Just to clarify: When Vanna "flips" a switch, she turns it from it's original position to the opposite position. So if a switch was on, she turns it off, and if a switch was off, she turns it on.
Which light switches are in the "on" position?
Just to clarify: When Vanna "flips" a switch, she turns it from it's original position to the opposite position. So if a switch was on, she turns it off, and if a switch was off, she turns it on.
Reply by admin
- March 11 2009 11:49:55 PM
This one is always on the site, but if you're not sure, I'd think about [hide]counting factor pairs for numbers[/hide].
Reply by Caprico
- January 11 2011 09:30:50 AM
Is the answer like[hide]All the numbers which have odd number of factors, including one and itself, will be in the "on" position[/hide]
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