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Mathematical_Recreations-Kraitchik-2e

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Probabilities 1~5

Finally, the probability of throwing a point and then of making

it is the product of the separate probabilities: for example,

(t)(%) = ft is the probability that the thrower will win by

throwing a 5 and making his point. In this way we arrive at

the following table of all possible results of one play:

Result of play

Probability

The thrower wins

by throwing a natural: 7 or 11

6+2 2 220

3"6= 9 = 990

by throwing and making 6 or 8

by throwing and making 5 or 9

5 5 25 125

2·-·--~-=-

36 5 + 6 198 990

444 88

2·-·--=- =990

364+6 45

by throwing and making 4 or 10 2.~._3_= ~ =~

363+6 18 990

in anyone of these ways

The thrower WBeil

by throwing craps: 2, 3, or 12

1 + 2 + 1 1 55

-

= 495

36 9

by throwing and losing 4 or 10 2.~._6_= 55

-

363+6 9 - 495

4 6 2 66

by throwing and losing 5 or 9 2·-·--- -

364 + 6 15 = 495

by throwing and losing

5 6 5 75

6 or 8 2·-·--- -

365+633 = 495

488 244

990 495

in anyone of these ways 251

495

From these results it appears that the thrower is at a slight

disadvantage, since the odds against him are 251 to 244.

This is interesting in the light of the almost universal feeling

among players (even honest ones) that they would rather

hold the dice. The game is made equitable if the dice

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