**Question:**

A king asked his 1000 soldiers to perform an unique exercise. There are 1000 closed doors and the first soldier will open all the doors, the second soldier will go to every second door and closes if its open and vice versa.the third soldier will go to every third door and closes if its open and vice versa..this goes on till the 1000th soldier finishes.At the end of the exercise how many doors will be open? PS: I solved the problem,its a bit tricky:)

Doors of perfect squares only

1,4,9,16,25,36 etc.,

Plzz tl d answer

Nt able to understand

Here's why.-

If you take it for a small number like 10, then the first soldier opens all 10 doors, the second soldier closes 9 so 1 remains open.

The third soldier opens 8 doors and 4th one closes 7.

This goes on till 10th soldier.

So for every odd number door, one door remains open.

So we get 5 open doors..

Increase this value from 10 to 100 and you get the answer. Half the numbers from 1-1000 are odd which makes it 500

. hope it __helps__

All perfectly squares

1

All perfect square will be open because they have odd number of factors. Odd time means open.

Pls explain the answer

How can you 31st door open.

__31__

1st doors is open...