"Genius is in-born, may it never be still-born."

"Oysters, irritated by grains of sand, give birth to pearls. Brains, irritated by curiosity, give birth to ideas."

"Brainpower is the bridge to the future; it is what transports you from wishful thinking to willful doing."

"Unless you keep learning & growing, the status quo has no status."

Saturday, May 9, 2009


[continue from the Last Post.]


Late one night, three teachers arrive for a convention in a neighbouring city. They check into a hotel, but since there’s only one room left, they agree to share it.

In view of the inconvenience caused, the hotel agrees to charge them only $30 for the night. Each person pays the cashier $10 and retires to the room.

Several minutes later, the cashier realises that since they have skipped dinner, he’ll give them back $5, thus reducing the room rate to $25.

He gives the bellboy five $1 notes and asks him to return this money to the teachers. Each teacher takes one of the dollars and then give the bellboy two dollars as a tip. Now each teacher has paid $9 and the bellboy has $2, giving a total of $29.

What happened to the missing dollar?


Four prisoners, A, B, C, and D, have been buried in sand, in a standing position, up to their shoulders. It is not possible for them to turn around; they can only look forwards. An opaque wall separates prisoner A from the rest.

What is known is that two of the prisoners are wearing black hats and two are wearing white hats. No prisoner has been told the colour of his own hat. They must work this out within 5 minutes, without speaking to one another, or they will all be killed.

Any prisoner can call out the colour of his hat if he is certain, but if his reasoning is incorrect, they will all be put to death.

If his reasoning is correct, they will all be saved. Is it possible to work out with certainty, the colour of a prisoner’s hat? If so, which prisoner calls out correctly?


Amigo Abadiano was standing on a riverbank, looking across to the far side. His amiga, Agnes, asks him to reckon how wide he thinks the river is. Amigo adjusts the rim of his hat, and then turns to look downstream.
In a few moments, he starts walking with very deliberate paces, along the riverbank.

A short while later, he turns and calls out, “About 50 metres, plus or minus a bit.”

How did he estimate the width of the river?

[To be continued in the Next Post. Excerpted from the Braintertainment segment of 'Unleashing Genius with the World's Most Powerful Learning Systems', by Dilip Mukerjea. All the images in this post are the intellectual property of Dilip Mukerjea.]

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