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Counting

How many 5 digit numbers start with a prime number and end with a prime number? Further no other digit in the number is a prime number. Also, no two digits of the 5 digit number are same .

A. 1440
B. 720
C. 360
D. 120

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9 comments

  1. Abhishek Tandon

    1440

    First digit options: 4 (2/3/5/7)
    Last digit options: 3 since no repetition.
    Middle 3 digits can’t be prime so, options 6 (0/1/4/6/8/9)

    So 4*6*5*4*3=1440

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