SOLUTION TO PUZZLE 5:100 LIGHT BULBS

SOLUTION TO PUZZLE 5:100 LIGHT BULBS

FOR QUESTION:puzzle 6:100 light bulbs

Person 1 will switch on all bulbs.Person 2 will operate on all even number bulbs.person 5 will operate on all bulbs which are multiple of 5.

Lets take bulb 24.which will be operated by (1&2),(3&4),(6&8),(12&24) all numbers are in pair.so if one person switched on,the other one will switch it off.So its final stage will be switch off.

Take this number 64(8^2),it will be operated by (1&2),(4&8),(16&32),(64) so 64 does not have pair to switch the bulb off atlast.so it will remain switched on finally.

This holds true for all square numbers(1,4,9,16,25,36,49,64,81,100).
 so the answer is 10 bulbs

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