(a). From a stack of 3 dice, one is taken and rolled twice. If, unknown to the gambler, one of the dice is weighted

\n(a). From a stack of 3 dice, one is taken and rolled twice.\n
If, unknown to the gambler, one of the dice is weighted and has a 1/9 chance of rolling a 6, what is the probability that the gambler rolls two 6\'s?\n

(b). If the gambler has rolled two sixes, what is the probability that he has rolled the weighted die?\n

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