9 lines
558 B
Markdown
9 lines
558 B
Markdown
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If a box contains twenty-one coloured discs, composed of fifteen blue discs and six red discs,
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and two discs were taken at random, it can be seen that the probability of taking two blue discs,
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`P(BB) = (15/21)x(14/20) = 1/2`.
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The next such arrangement, for which there is exactly 50% chance of taking two blue discs at random,
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is a box containing eighty-five blue discs and thirty-five red discs.
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By finding the first arrangement to contain over `10^12 = 1,000,000,000,000` discs in total,
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determine the number of blue discs that the box would contain.
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