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ChalcoDoror
Veteran
Joined: 12 Oct 2005 Posts: 148
Green #116 The Rice Gambit
The Rice Gambit wrote:
According to legend, the game of chess was invented hundreds of years ago by the Grand Vizier Sissa Ben Dahir, for King Shirham of India. King Shirham was so delighted with the new game that he offered his Grand Vizier any reward he wished for.
"Majesty, I desire but one grain of rice on the firest square, two grains on the second, four on the third, eight on the fourth and son on, until every square on the board is covered."
"Is that all you wish, Sissa, you fool?" exclaimed the astonished King.
But Sissa's request was far from foolish. How many grains of rice had Sissa asked for?
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Posted: Thu Nov 24, 2005 4:56 am
number9dream
Decorated
Joined: 22 Apr 2005 Posts: 222 Location: Newcastle, UK
Well I'm no mathematician but i think it could be
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2 to the power of 63 +1 = 9223372036854775809
_________________Sometimes I think the surest sign that intelligent life exists elsewhere in the universe is that none of it has tried to contact us.
Posted: Thu Nov 24, 2005 5:15 am
sixsidedsquare
Unfettered
Joined: 24 Mar 2005 Posts: 409 Location: 60E
I'm no mathmo either but using MATLAB, I get it to be:
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2080 grains
Posted: Thu Nov 24, 2005 6:43 am
European Chris
Unfictologist
Joined: 19 Jul 2005 Posts: 1264 Location: London's trendy Whitechapel
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"I'm no mathmo either but using MATLAB, I get it to be:2080 grains"
No, that would be an arithmetic progression 1,2,3,4....63,64.
I don't think number9dream's answer is quite right either, I think that would be 1 away from the number of rice grains on the 64th square.
I think, and I might be wrong.
2^0+2^1+2^2.....2^62+2^63=2^64-1=18446744073709600000.
Quote:
But Sissa's request was far from foolish.
Well it was-he asked for rice. It's not very flavoursome is it.
EDIT: to add 1 and to tidy it up and to change it to TAKE one.
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Posted: Thu Nov 24, 2005 7:05 am
Last edited by European Chris on Thu Nov 24, 2005 12:09 pm; edited 4 times in total
number9dream
Decorated
Joined: 22 Apr 2005 Posts: 222 Location: Newcastle, UK
European Chris wrote:
I don't think number9dream's answer is quite right either,
Told you i was no mathmo, yours sounds much more like it
_________________Sometimes I think the surest sign that intelligent life exists elsewhere in the universe is that none of it has tried to contact us.
Posted: Thu Nov 24, 2005 7:33 am
sixsidedsquare
Unfettered
Joined: 24 Mar 2005 Posts: 409 Location: 60E
oops pays to read the question right.
Spoiler (Rollover to View):
Making it a bit more accurate it's 18446744073709551616 grains
Still not actually sure if thats rounded or not..
Cheers to snowchyld for the unrounded number
Posted: Thu Nov 24, 2005 7:57 am
European Chris
Unfictologist
Joined: 19 Jul 2005 Posts: 1264 Location: London's trendy Whitechapel
Durh, I was using a scientifc calculator and didn't even think about it-I'm a spaz.
Also, surely you have to add one as well. The number of grains must be an odd number as 2^x=even (not when x=0) and we also have 2^0=odd. I've just been for a Thursday lunchtime Gins and I'm feeling a bit slow.
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Posted: Thu Nov 24, 2005 9:17 am
sixsidedsquare
Unfettered
Joined: 24 Mar 2005 Posts: 409 Location: 60E
Well duh me, it's just like binary
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The largest number that can be represented by 64 bits is 2^64 -1
being 18446744073709551615, an odd number like you said European Chris.
See what we got for not having the mathmo's around
Posted: Thu Nov 24, 2005 9:34 am
chichiri
Decorated
Joined: 31 Oct 2005 Posts: 207
Confirmed that!
no da
Posted: Thu Nov 24, 2005 10:57 am
European Chris
Unfictologist
Joined: 19 Jul 2005 Posts: 1264 Location: London's trendy Whitechapel
European Chris wrote:
Durh, I was using a scientifc calculator and didn't even think about it-I'm a spaz.
Also, surely you have to add one as well. The number of grains must be an odd number as 2^x=even (not when x=0) and we also have 2^0=odd. I've just been for a Thursday lunchtime Gins and I'm feeling a bit slow.
Take one rather. [note to self] must read and understand the question) [/note to self]
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Posted: Thu Nov 24, 2005 12:07 pm
GasparLewis
Unfettered
Joined: 19 Nov 2005 Posts: 474 Location: vicinty of NYC
Considering all the old doubling games, I do believe the sum total is:
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2^65 - 1
Whatever that may calculate to.
Posted: Thu Nov 24, 2005 2:32 pm
European Chris
Unfictologist
Joined: 19 Jul 2005 Posts: 1264 Location: London's trendy Whitechapel
Spoiler (Rollover to View):
No, in general the sum of all the grains of rice is 2^x-1.
This is derived from 2^0+2^1+....2^64.
And it x=64 due to 8x8=number of squares
_________________
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Posted: Thu Nov 24, 2005 3:40 pm
spugmeistress
Unfettered
Joined: 22 Feb 2005 Posts: 460 Location: manchester, uk
I stuck 111......1111 (64x 1's, if you get what I mean?) into a binary -> decimal converter, that should've got the answer, right?
Spoiler (Rollover to View):
cept it came out with 18,446,744,073,709,552,000
which is the same as your answer up until the end. guess it could have rounded without me asking it to?
can anyone even start to describe any of these numbers in words?! i'm lost about 9 digits past the decimal point :)
hmm i wonder how much that many grains of rice would weigh...
to be fair, rice might not be flavoursome but i bet he'd get a fair bit out of sticking it on ebay ;)
rach =)
Posted: Thu Nov 24, 2005 9:26 pm
nasixi
Greenhorn
Joined: 25 Nov 2005 Posts: 6
After trying a couple of obvious answers using my calculator, I used excel, simply doubling the number each time. Unless I've done something wrong, my answer came out as
Spoiler (Rollover to View):
18446744073709500000
But that didn't work.
Then again, I've had a few drinks, so my typing might have suffered!
Posted: Fri Nov 25, 2005 6:42 pm
Forgery
Decorated
Joined: 22 Nov 2005 Posts: 158
Is there difinatly a numerical answer to this?? I don't have the card so I cannot see how the answer should be inputted but...
Spoiler (Rollover to View):
I've heard this puzzle many of times and everytime I have heard it, I have also been told 'If you did this (doubling the rice per square) there will not be enough grains of rice in the world to fit onto the chess board.' That's why Siss's request was far from foolish, because it is impossible
Ok from reading the question again this may not be write because the question does state how many, but I may be on to something, I dunno lol
Posted: Fri Nov 25, 2005 8:48 pm
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