Registan,
I'll try one more time.
This time my answer is 18446744073709600000 (or 1.84467E+19)

I think this is the right answer, but still not sure...

The Alchemist

At last you have the answer, but a bit wrong. It's geometrik progression. b1=1, q=2 n=64 b64=b1*q"(n-1)=1*2"63=2"63=9223372036854775808 S64=(b1*q"n-1)/(q-1)=(1*2"64-1)/1=2"63-1=18446744073709551616-1=18446744073709551615

So the right answer is: 18446744073709551615  (There are not enough rice amount of this in the world. )

OK, next one: How do you explain this?

The area of a right triangle is computed by multiplying the base times the height and dividing by two. The pieces of the puzzle have an area of 32 square units. Although they can be assembled to form what appears to be a 13×5 right triangle, they actually form quadrilaterals that are slightly smaller or slightly bigger than a 13×5 right triangle. The long side of the these triangles, i.e, the hypotenuse, is not a straight line.

The top figure has an area of 32 square units. The bottom figure, including the empty square, has an area of 33 square units. A real 13×5 right triangle would have an area of 32.5 square units. The distortion is difficult to see because one square of the picture is approximately 3% of the area.

The distortion can be seen more clearly when the empty square constitutes a larger percentage of the area, as in the figure below where 1 square represents 13% of the area.

The Alchemist

At a party, everyone shook hands everybody else. There were 66 handshakes. How many people were at the party?

The Alchemist

I think there were 12 people, weren't there?

Yes they were 12 people at the party...

The Alchemist

A bear walks south for one kilometer, then it walks west for one kilometer, then it walks north for one kilometer and ends up at the same point from which it started.
Question: what color was the bear?

The Alchemist

White

No you made a little mistake,
the bear was not white, it was WHITE.... (just like rice question)

The Alchemist