If there are 20,000 light bulbs in a row, and they are all OFF.
All of the lights have one of them strings to turn it from on to off, or off to on..
First go down the row and pull every lights string.
So you pull lights 1,2,3,4,5...
Now do it again pulling every 2nd lights string
So you pull lights 2,4,6,8,10...
Now the 3rd, 3,6,9,12,15..
4th, 4,8,12,16...
Keep doing this until you get to the end. Then end is when you pull every 20,000th lights string...(which means you only pull the string of the last light)
At the end, how many lights are ON?
And explain which ones will be on...
Have fun...
2007-10-30
06:40:10
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2 answers
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asked by
Randy C
2