Interview Puzzle

• Puzzle 1 : Find the switch

To re-iterate the questions: You have 1 bulb inside the room and 3 switches outside the room. You need to find which switch controls the bulb, and you have only 1 chance to enter the room.  Clue: Use your senses Heat :)
Solution:

• Turn on switch 1
• Turn on switch 2, and switch it off after sometime
• Don't do anything with switch 3.

Now enter the room...

• If light is on: Its switch 1
• If it is off, touch the bulb: It its hot it is controlled by switch 2
• If its off and not hot: It is switch 3

• Puzzle 2 : Measuring 4lts water using 3lt and 5lt can's.

Solution 1

• Fill the 5 litre can from the tap
• Empty the 5 litre can into the 3 litre can - leaving 2 litres in the 5 litre can.
• Pour away the contents of the 3 litre can.
• Fill the 3 litre can with the 2 litres from the 5 litre can - leaving 2 litres in the 3 litre can.
• Fill the 5 litre can from the tap.
• Fill the remaining 1 litre space in the 3 litre can from the 5 litre can.
  Leaving 4 litres in the 5 litre can.

Solution 2

• Fill the 3 litre can from the tap.
• Empty the contents of the 3 litre can into the 5 litre can.
• Fill the 3 litre can from the tap.
• Empty the contents of the 3 litre can into the 5 litre can. - Leaving the 5 litre can full and 1 litre in the 3 litre can.
• Pour away the contents of the 5 litre can
• Pour the 1 litre from the 3 litre can into the 5 litre can.
• Fill the 3 litre can from the tap.
• Empty the contents of the 3 litre can into the 5 litre can.
  Leaving 4 litres in the 5 litre can.

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