Find the bulb for the switch

There is a room with a door (closed) and three light bulbs. Outside the room there are three switches, connected to the bulbs. You may manipulate the switches as you wish, but once you open the door you can't change them. Identify each switch with its bulb.

Source : My brother & http://www.sellsbrothers.com/fun/msiview/default.aspx?content=question.htm

Find direction of rotation

Imagine a disk spinning like a record player turn table. Half of the disk is black and the other is white. Assume you have an unlimited number of color sensors. How many sensors would you have to place around the disk to determine the direction the disk is spinning? Where would they be placed?

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Pay for 7 days using 1 7-segment gold bar and 2 cuts

You've got someone working for you for seven days and a gold bar to pay them. The gold bar is segmented into seven connected pieces. You must give them a piece of gold at the end of every day. If you are only allowed to make two breaks in the gold bar, how do you pay your worker?

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Rope Escape

Rajeev is trapped atop a building 200m high. He has with him a rope 150m long.There is a hook at the top where he stands.

Looking down, he notices that midway between him and the ground, at a height of 100m, there is a ledge with another hook. In his pocket lies a Swiss knife.

How might he be able to come down using the rope, the two hooks and the Swiss knife?

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[ALGO] Six Colored Balls

We have two red, two green and two yellow balls. For each color, one ball is heavy and the other is light. All heavy balls weigh the same. All light balls weigh the same. How many weighings on a beam balance are necessary to identify the three heavy balls?

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