Thursday, June 11, 2009

Solving Historical Elementary Mathematics Problems #3

Poet Li Bai’s jug contained some wine. Every time he passed by a wine shop, he would top up the wine in the jug so that the amount was doubled. When he passed by beautiful flowers, he would drink 1 litre of wine from the jug. Along the way, he passed by wine shops and beautiful flowers three times alternatively and finished all the wine in the jug.
What was the amount of wine originally in Li Bai’s jug?

(Tang Dynasty, China)

18 comments:

  1. By working backwards...

    At Beautiful Flowers (end) = 0 + 1 = 1 litre

    At Wine Shop = 1 / 2 = 0.5 litre


    At Beautiful Flowers = 0.5 + 1 = 1.5 litres

    At Wine Shop = 1.5 / 2 = 0.75 litres

    At Beautiful Flowers = 0.75 + 1 = 1.75 litres

    At Wine Shop (Beginning) = 1.75 / 2 = 0.875 litres

    Ans: 0.875 litres??

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  2. Zhi Xian and Zhi TingJune 12, 2009 at 10:35 AM

    still thinking......

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  3. Zhi Xian and Zhi TingJune 12, 2009 at 10:41 AM

    There are 21 H1N1 cases in Singapore!

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  4. Zhi Xian and Zhi TingJune 12, 2009 at 11:43 AM

    It must end at the flower shop,which means there is 1litre before he drinks it.This is the top up of the wine at the wine shop.So 1litre/2=500ml.When see beautiful flower he drinks 1litre,so 1litre+500ml=1litre500ml. This is the top up for the wine,so 1litre500ml/2=750ml.Now add:1litre +750ml=1750ml(when he sees beautiful flower).This is the answer,1750ml/2=875ml!

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  5. Zhi Xian and Zhi TingJune 12, 2009 at 11:55 AM

    Anyway what does it means by 3 times alternatively.We don't understand:(

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  6. Zhi Xian and Zhi TingJune 12, 2009 at 2:56 PM

    If not,is the answer 1 litre 500ml?

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  7. The World Health Organisation (WHO)has declared the first pandemic in 40 years and raised its pandemic alert level to the maximum level of six.

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  8. No more quarantine.

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  9. I think that the answer has to be solved using backwards, like Han Chen:

    He must end at the flower shop as if he ends at the wine shop, his wine would increase.

    So, at the flower shop, he would increase his wine by 1 litre.

    Next, he went to the wine shop and decrease his wine by dividing two. the answer would be 500ml.

    He went to the flower shop and increase his wine to be 1500ml.

    He again went to the wine shop and his wine became 750ml.

    He went to the flower shop and his wine became 1750ml.

    Finally, he went to the wine shop and his wine became 875ml.

    The answer is then 875ml.

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  10. My answer is definitely correct!!

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  11. Hey! Who deleted all the followers!

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  12. Whoops, I forgot to sign in, that's why

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  13. Zhi Xian and Zhi TingJune 15, 2009 at 8:30 AM

    There are 40 cases of H1N1 in Singapore!

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  14. There are now 50 cases.

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  15. Mr Soh, no more questions for us to solve?

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  16. Who is Igor Stravinsky?

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  17. He was a composer, pianist and a conductor. He was also considered by many to be one of the most important and influential composers of 20th century music. He was so famous that I do not know what to say!!

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  18. Just to ask, can we have a class t-shirt?

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