+ Reply to Thread
Results 1 to 10 of 10

calculating percentage of percentage

  1. #1
    Registered User
    Join Date
    10-10-2013
    Location
    noyb
    MS-Off Ver
    Excel 2003
    Posts
    2

    calculating percentage of percentage

    How does one get "X" in excel from the formula 100=X-(X*21%)-(X*2.7%) ?

    Background: Credit cards take a percentage of the VAT inclusive amount. I would like this credit card cost to be automatically included in total VAT inclusive cost.

    For example, VAT is 21% and credit card fee is 2.7% on the total VAT inclusive amount. A theoretical VAT inclusive amount of 121 would have a credit card cost of 3.267 and a VAT cost of 21, so the net amount is not 100 but 96.733

    What would the VAT inclusive amount need to be to have a net amount of 100? And how does one put this in an excel formula?

  2. #2
    Forum Expert
    Join Date
    04-22-2013
    Location
    .
    MS-Off Ver
    .
    Posts
    4,418

    Re: calculating percentage of percentage

    100=X-(X*21%)-(X*2.7%)
    Convert percentage to decimals:
    100=X-(X*0.21)-(X*0.027)
    Divide both side by X
    100/X=X/X-(x/x*0.21)-(x/x*0.027)=1-0.21-0.027
    Multiply both sides by x, then divide both sides by (1-0.21-0.027)
    X=100/(1-0.21-0.027)

    I think.

  3. #3
    Forum Expert XOR LX's Avatar
    Join Date
    04-18-2013
    Location
    Turin, Italy
    MS-Off Ver
    Office 365
    Posts
    7,742

    Re: calculating percentage of percentage

    "Divide both side by X" (x<>0)

    Regards
    Click * below if this answer helped

    Advanced Excel Techniques: http://excelxor.com/

  4. #4
    Forum Expert
    Join Date
    04-22-2013
    Location
    .
    MS-Off Ver
    .
    Posts
    4,418

    Re: calculating percentage of percentage

    Ha

    100=X-(X*21%)-(X*2.7%)
    Convert percentage to decimals:
    100=X-(X*0.21)-(X*0.027)
    Factorise right side by X:
    10=X*(1-0.21-0.027)
    Divide both side by (1-0.21-0.027):
    X=100/(1-0.21-0.027)

    Better?

  5. #5
    Forum Expert XOR LX's Avatar
    Join Date
    04-18-2013
    Location
    Turin, Italy
    MS-Off Ver
    Office 365
    Posts
    7,742

    Re: calculating percentage of percentage

    Much better!

  6. #6
    Registered User
    Join Date
    10-10-2013
    Location
    noyb
    MS-Off Ver
    Excel 2003
    Posts
    2

    Re: calculating percentage of percentage

    Quote Originally Posted by yudlugar View Post
    Ha

    100=X-(X*21%)-(X*2.7%)
    Convert percentage to decimals:
    100=X-(X*0.21)-(X*0.027)
    Factorise right side by X:
    10=X*(1-0.21-0.027)
    Divide both side by (1-0.21-0.027):
    X=100/(1-0.21-0.027)

    Better?
    Sometimes life is so, so simple one doesn't see it and needs to be told. Thank you!!!

  7. #7
    Forum Expert
    Join Date
    04-22-2013
    Location
    .
    MS-Off Ver
    .
    Posts
    4,418

    Re: calculating percentage of percentage

    I'd argue that the other one is valid when x=0 also though, as it would give you 0/0 which is possible

  8. #8
    Forum Expert XOR LX's Avatar
    Join Date
    04-18-2013
    Location
    Turin, Italy
    MS-Off Ver
    Office 365
    Posts
    7,742

    Re: calculating percentage of percentage

    Haha!

    So you claim - mathematicians have been debating the true definition of 0/0 for centuries!

  9. #9
    Forum Expert
    Join Date
    04-22-2013
    Location
    .
    MS-Off Ver
    .
    Posts
    4,418

    Re: calculating percentage of percentage

    I like the:
    0/0=y
    therefore
    0*y=0
    therefore y can be any number
    arguement...

  10. #10
    Forum Expert XOR LX's Avatar
    Join Date
    04-18-2013
    Location
    Turin, Italy
    MS-Off Ver
    Office 365
    Posts
    7,742

    Re: calculating percentage of percentage

    Yes! A classic Christmas Cracker teaser for budding young mathematicians everywhere!

+ Reply to Thread

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Replies: 1
    Last Post: 01-13-2013, 08:39 PM
  2. Calculating a percentage with the end percentage in mind
    By Shadowshady in forum Excel General
    Replies: 2
    Last Post: 06-17-2006, 04:45 AM
  3. Replies: 2
    Last Post: 02-01-2006, 12:50 PM
  4. [SOLVED] Calculating Percentage
    By mconnolly in forum Excel Formulas & Functions
    Replies: 0
    Last Post: 09-06-2005, 03:05 PM
  5. Calculating Percentage
    By mconnolly in forum Excel Formulas & Functions
    Replies: 0
    Last Post: 09-06-2005, 12:05 AM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts

Search Engine Friendly URLs by vBSEO 3.6.0 RC 1