Original number from percentage of number

Discussion in 'Basic Math' started by AccessShell, May 2, 2020.

  1. AccessShell

    AccessShell

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    It' been more than 50 yrs since I was in high School, but this problem is bothering me.

    If I have a number and I need 85% on that number, it easy. Just multiply the number by .85.

    But I need to turn that around. If the the 85% number and I need to get the original number, I cant just multiply by 1.15.

    I hope I explained it correctly. Going up is what I cant figure out.

    Thanks
     
    AccessShell, May 2, 2020
    #1
  2. AccessShell

    Ian Administrator

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    Rather than multiply by 0.85, divide by 0.85 and you have the original number :)
     
    Ian, May 5, 2020
    #2
  3. AccessShell

    AccessShell

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    Thanks. thread closed
     
    AccessShell, May 5, 2020
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  4. AccessShell

    nycmathguy

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    Say the number is 100.

    Then 85% of 100 = 0.85(100) = 85.

    To get the original number back, divide 85 by 0.85.

    So, 85 รท 0.85 = 100, the original number.

    In a general sense, let n = the original number.

    Then 0.85n = m, where m is the new number.

    To get back the original number n, we do this:

    m/0.85 = n, the original number.
     
    nycmathguy, Jul 6, 2021
    #4
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