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    answersplease's Avatar
    answersplease Posts: 11, Reputation: 1
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    #1

    Oct 19, 2007, 01:49 PM
    A math riddle
    I am a number who is greater than 40 and less than 90. I am proud to be a prime number. My ones digit is also a prime number and so is my tens digit. If you subtract my ones digit form my tens digit, the answer is not 2. What number am I?:eek:
    galactus's Avatar
    galactus Posts: 2,271, Reputation: 282
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    #2

    Oct 19, 2007, 03:14 PM
    This is a matter of deduction. There only so many primes between 40 and 90. List them out and check the criteria.

    41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89
    letmetellu's Avatar
    letmetellu Posts: 3,151, Reputation: 317
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    #3

    Oct 19, 2007, 06:53 PM
    Quote Originally Posted by answersplease
    I am a number who is greater than 40 and less than 90. I am proud to be a prime number. My ones digit is also a prime number and so is my tens digit. If you subtract my ones digit form my tens digit, the answer is not 2. What number am I?:eek:
    I say 71
    galactus's Avatar
    galactus Posts: 2,271, Reputation: 282
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    #4

    Oct 19, 2007, 07:18 PM
    No, 1 is not a prime. How about 73?
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