A number of cats got together and decided to kill between them 999919 mice. Every cat killed an equal number of mice. Each cat killed more mice than there were cats. How many cats do you think there were ?

There were 991 cats, and each of them killed 1009 mice.

To check, 991*1009 = 999919

Solution:

Get the prime factorization of 999919
The prime factors are 991 and 1009 only

9 Responses to “A number of cats got together and decided to kill between them 999919 mice. Every cat killed an equal number o”

  • vijay says:

    mice were too smart for cats. they all ran away
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  • Bracha says:

    One?

    First you must factorize 999919. But I haven’t found any factors of 999919 yet.

    I think 1 is correct. Because the cat killed more mice (999919) than there were cats (1).
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  • armless_man says:

    There are 991 cats and they killed 1009 mice each
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  • nwyrk2552 says:

    991 cats each killed 1,009 mice.
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  • BB says:

    There were 991 cats, and each of them killed 1009 mice.

    To check, 991*1009 = 999919

    Solution:

    Get the prime factorization of 999919
    The prime factors are 991 and 1009 only
    References :

  • rahul s says:

    1 cat
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  • ^K-A^ says:

    It depends, I guess.
    A number of cats "decided" to kill 999919 mice. It is unknown whether they did kill them all.
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  • finelearner says:

    Using fermat’s method find the Prime factor.
    Now Let n = 999919 and square root is appx 1000
    so i = 1000 , we find that sqrt(999^-999919)
    = sqrt(81) = 9
    Then 1000 – 9= 991 and 1000+ 9 = 1009
    By multificaton we verify that 991*1009 = 999919
    As Each cat killed more mice than the numebr of cats
    Hence there were 991 cats and each cat killed 1009 mice.
    References :

  • Pranil says:

    Dear finelear
    Sorry, as I can not email you, I am contacting here.
    Please explain the step below.
    we find that sqrt(999^-999919)
    = sqrt(81) = 9
    If possible e-mail me for number factors of 24999 by this method.
    References :

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