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moonbeam wrote:I make it that the odds of turning over the first face down card correctly are 160 in 221.
Lawrence wrote:moonbeam wrote:I make it that the odds of turning over the first face down card correctly are 160 in 221.
Cos I'm a maths geek can I see your workings on how you got to this figure?
moonbeam wrote:I worked out the odds of turning over the first card correctly, but this does not take into account the fact that you can change the card if you want:
If first card is a 2 - guess higher and you have a 48 in 51 chance of being correct.
If first card is a 3 - guess higher and you have a 44 in 51 chance of being correct.
If first card is a 4 - guess higher and you have a 40 in 51 chance of being correct.
If first card is a 5 - guess higher and you have a 36 in 51 chance of being correct.
If first card is a 6 - guess higher and you have a 32 in 51 chance of being correct.
If first card is a 7 - guess higher and you have a 28 in 51 chance of being correct.
If first card is a 8 - guess is irrelevant as both will give an equal chance of being correct - 24 in 51.
If first card is a 9 - guess lower and you have a 28 in 51 chance of being correct.
If first card is a 10 - guess lower and you have a 32 in 51 chance of being correct.
If first card is a J - guess lower and you have a 36 in 51 chance of being correct.
If first card is a Q - guess lower and you have a 40 in 51 chance of being correct.
If first card is a K - guess lower and you have a 44 in 51 chance of being correct.
If first card is an A - guess lower and you have a 48 in 51 chance of being correct
Now each of the above has an equal 1 in 13 chance, so I make it that the odds of turning over the first face down card correctly are 160 in 221.
Part-Timer wrote:Maybe I have got my maths wrong, but isn't it actually about 10%? Lawrence, I think you might have calculated on the basis of too many cards - there are eight guesses in total, not ten.
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