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Math Help - Divisibility problem

  1. #1
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    Divisibility problem

    IF m is divisible by 5 what is the largest number that must be evenly divisible into 5m + 25 ? Ans=25
    How did they get 25 here?
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  2. #2
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    Re: Divisibility problem

    Quote Originally Posted by MikeNoob View Post
    How did they get 25 here?
    If m is divisible by 5 then we can write m=5k So 5m+25=25k+25=25(k+1)
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  3. #3
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    Re: Divisibility problem

    honestly, it seems the correct answer is 5m + 25, which surely divides 5m + 25 (and may be bigger than 25, if m is larger than 5).
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  4. #4
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    Re: Divisibility problem

    I take 'evenly divisible by 25' to mean not the number itself. I take the question to mean what is the largest number that will divide into 5m+25 for all m.
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  5. #5
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    Re: Divisibility problem

    Quote Originally Posted by biffboy View Post
    I take 'evenly divisible by 25' to mean not the number itself. I take the question to mean what is the largest number that will divide into 5m+25 for all m.
    I still dont get how they got
    25 ?
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