the chess puzzle

[foleygee]

hi guys ,really scratching my head here and need your help , am an avid chess player and remember the old fable of the reward granted by the emperor for inventing chess. it goes on about he asked for a grain of rice on one square then 2 on the next and so on, exponential growth went on and he ended up very wealthy and powerful man due to the emperor's naivety .So moving on the figure of rice by square 64 on the chess board agreed by all parties comes to 18,446,744,073,709,551,615 or just over 18 quintillion. however i looked around for the weight of that calculation in tonnes of rice terms and this is my problem, i have seen various and vast differences on the final figure , eg 210 billion tonnes , another said 1.4 trillion another said 5 trillion tonnes. here's what i know , i will accept as more or less there are 50,k rice in a kilo of rice (nice easy figure as well) therefore if a 1000 kilos = 1 tonne (metric) then 50,000 x 1000 = 50 million rice in a tonne yes? so to get the weight its must be 18,446,744,073,709,551,615 pieces of rice divided by 50,000,000. first is my logic sound ? 2nd how may tonnes did it work out to

 

[Deleted member 4993]

hi guys ,really scratching my head here and need your help , am an avid chess player and remember the old fable of the reward granted by the emperor for inventing chess. it goes on about he asked for a grain of rice on one square then 2 on the next and so on, exponential growth went on and he ended up very wealthy and powerful man due to the emperor's naivety .So moving on the figure of rice by square 64 on the chess board agreed by all parties comes to 18,446,744,073,709,551,615 or just over 18 quintillion. however i looked around for the weight of that calculation in tonnes of rice terms and this is my problem, i have seen various and vast differences on the final figure , eg 210 billion tonnes , another said 1.4 trillion another said 5 trillion tonnes. here's what i know , i will accept as more or less there are 50,k rice in a kilo of rice (nice easy figure as well) therefore if a 1000 kilos = 1 tonne (metric) then 50,000 x 1000 = 50 million rice in a tonne yes? so to get the weight its must be 18,446,744,073,709,551,615 pieces of rice divided by 50,000,000. first is my logic sound ? 2nd how may tonnes did it work out to

So pull out your calculator and divide!

50,000,000 *2 = 10^8

18,446,744,073,709,551,615 *2 = 37 * 10^(18)

# of tonne ~ 37 * 10^10 ~ 370 billion tonne according to your assumptions.