Others Maths Puzzle

I have mixed 13 decks of cards.

What is the minimum number of cards must be taken out from the above mixed cards to guarantee at least one 'four of a kind'.

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Others Other Question

salman's youth lasted one sixth of his life. He grew a beard after one twelfth more. After one seventh more of his life, he married. 5 years later, he and his wife had a son. The son lived exactly one half as long as his father, and salman died four years after his son.

How many years did salman live? A number can be multiplied by multiple of nine
i.e 9 18 27 36 45 ...and the resulting number consist of only one digit.
Can you identify the number ?