# How can you figure out which light switch goes to which light bulb by only making 1 trip upstairs?

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There are 3 switches downstairs, each corresponding to one of the light bulbs upstairs.
How can you figure out which light switch goes to which light bulb by only making 1 trip upstairs?

posted Jan 12

You turn on one light bulb. Leave it on for a while. Then, turn that one off and turn another one on. Go upstairs. One light bulb will be cold, one will be warm, and one will be on.

When a bulb is left on for some minutes, it will get heated up.
So turn 1st switch on and leave for considerable amount of time so that corresponding bulb will be heated up.
Now turn 1st one off and turn on 2nd one,
Then upstairs.

The bulb which is glowing is of second switch.
The bulb which is hot and not glowing now, is of first switch.
The bulb which is cool and also not glowing is of third switch.

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+1 vote

There are three switches downstairs. Each corresponds to one of the three light bulbs in the attic. You can turn the switches on and off and leave them in any position.
How would you identify which switch corresponds to which light bulb, if you are only allowed one trip upstairs?

Welcome to the deadly game placed by the serial killer Jigsaw. You are tied to a chair and you cant move your hands or get up. Jigsaw shows you an empty gun with all the six chambers empty. He puts two bullets in the adjacent chambers and then close the barrel. He spins it and then point the gun to your head. The first shot snaps. It was an empty slot.

Now before pressing the trigger again, he asks you whether to pull the trigger or to spin the barrel first and then pull the trigger.

If the second shot goes empty, you will be spared by him. What will you choose?

Also think what will you chose if the bullets are not in the adjacent chambers.