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A typical PIN (personal identification n...

A typical PIN (personal identification number) is a sequence of any four symbols chosen from the 26 letters in the alphabet and the ten digits. If all PINs are equally likely, what is the probability that a randomly chosen PIN contains a repeated symbol?

Text Solution

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Solution. A PIN is a sequence of four symbols selected from 36 (26 letters + 10 digits) symbols.
There are `36 xx 36 xx 36 xx 36 = 364 = 1,679,616` PINs in all.
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Knowledge Check

  • Three digits are chosen at random from 1, 2, 3, 4, 5, 6, 7, 8 and 9 without repeating any digit. What is the probability that the product is odd?

    A
    `(2)/(3)`
    B
    `(7)/(48)`
    C
    `(5)/(42)`
    D
    `(5)/(108)`

  • Three digits are chosen at random from 1,2,3,4,5,6,7,8 and 9 without repeating any digit. What is the probability that the product is odd?

    A
    `(2)/(3)`
    B
    `(7)/(48)`
    C
    `(5)/(42)`
    D
    `(5)/(108)`

  • Three distinct vertices are chosen at random from the vertices of a gien regular polygon of (2n+1) sides. Let all such choices are equalty likely and the probability that the centre of the given polygon lies in the interior of the triangle determined by these three chosen random points is (5)/(14) . The number of diagonals of the polygon is equal to

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