# Innumerate needs formula! (Simple - help!) **URL:** \ **Category:** Factual Questions\ **Created:** [August 26, 1999, 3:53am UTC](https://boards.straightdope.com/t/innumerate-needs-formula-simple-help/2867 "1999-08-26T03:53:00Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![Stoid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/stoid/32/272_2.png) [@Stoid](https://boards.straightdope.com/u/Stoid)\ **Post date:** [August 26, 1999, 3:53am UTC](https://boards.straightdope.com/t/innumerate-needs-formula-simple-help/2867/1 "1999-08-26T03:53:00Z")
I need the formula to arrive at the following. N is 85% of \_\_\_\_\_ (number)? Sample: I receive $145 from you. You tell me that this is my percentage, which we both know is 85% of the total number. You receive 15% of the total number. What is the total number? What is your 15%? And what is the formula I use to arrive at these numbers? (I need it frequently, and I never remember it. I’m an idiot at math.) I would be forever in your debt… ---
**Author:** ![TheIncredibleHolg](https://avatars.discourse-cdn.com/v4/letter/t/8797f3/32.png) [@TheIncredibleHolg](https://boards.straightdope.com/u/TheIncredibleHolg)\ **Post date:** [August 26, 1999, 3:27pm UTC](https://boards.straightdope.com/t/innumerate-needs-formula-simple-help/2867/2 "1999-08-26T15:27:00Z")
There are two basic things to remember (I may be stating the obvious, but I don’t know what level of knowledge to expect from you): 1. Percent are nothing more than hundredths, i.e. 85% = 85/100 = .85 2. Taking a percentage **of** something means taking the percentage **times** that something, i.e. 85% of $200 = 85/100 of $200 = .85 \* $200 = $170 Now for your question: If you know that N = 85% of X, you really know that N = .85 \* X. Solve this for X, and you get X = N / .85 Hope that helps. Now your exercise is to do the calculation for your sample figure of $145, for both the 85% and the 15% shares. Do it right here so we can verify. After that, you can go play. 🙂 Oh, and concerning that debt you’re in: It’s exactly 15% of the total… ---
**Author:** ![cmkeller](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cmkeller/32/118_2.png) [@cmkeller](https://boards.straightdope.com/u/cmkeller)\ **Post date:** [August 26, 1999, 3:30pm UTC](https://boards.straightdope.com/t/innumerate-needs-formula-simple-help/2867/3 "1999-08-26T15:30:00Z")
Divide N by .85. Or, to do it without dividing by a decimal, multiply N by 20, then divide the product by 17. * * * Chaim Mattis Keller [ckeller@schicktech.com](mailto:ckeller@schicktech.com) “Sherlock Holmes once said that once you have eliminated the impossible, whatever remains, however improbable, must be the answer. I, however, do not like to eliminate the impossible. The impossible often has a kind of integrity to it that the merely improbable lacks.” – Douglas Adams’s Dirk Gently, Holistic Detective ---
**Author:** ![system](https://global.discourse-cdn.com/straightdope/original/2X/e/e489c3b7d8fce19c4b355dd4fc3f88cc39c34b87.png) [@system](https://boards.straightdope.com/u/system)\ **Post date:** [August 26, 1999, 3:31pm UTC](https://boards.straightdope.com/t/innumerate-needs-formula-simple-help/2867/4 "1999-08-26T15:31:00Z")
Simple algebra. x = 0.85 \* y therefore y (total) = x / 0.85 and the rest (15 %) is y - x or y \* 0.15 if 85% = 145 then total = 145 / 0.85 = 170.59 (approx.) 15% = 170.59 - 145 = 25.59 or 15% = 170.59 \* 0.15 = 25.59 (approx.) * * * Jacques Kilchoer Workers of the world, unite! You have nothing to lose but your chains. ---
**Author:** ![AHunter3](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ahunter3/32/368_2.png) [@AHunter3](https://boards.straightdope.com/u/AHunter3)\ **Post date:** [August 26, 1999, 4:01pm UTC](https://boards.straightdope.com/t/innumerate-needs-formula-simple-help/2867/5 "1999-08-26T16:01:00Z")
Let’s see…N is 85/100 of X, solve for X. Divide N by 85, multiply the results by 100, you get X. 100N/85=X * * * Designated Optional Signature at Bottom of Post ---
**Author:** ![BigRoryG](https://avatars.discourse-cdn.com/v4/letter/b/f07891/32.png) [@BigRoryG](https://boards.straightdope.com/u/BigRoryG)\ **Post date:** [August 26, 1999, 4:53pm UTC](https://boards.straightdope.com/t/innumerate-needs-formula-simple-help/2867/6 "1999-08-26T16:53:00Z")
The easiest way i ever figured out to do percentages is divide the number by the percentage you know it is so that it equals 1% then multiply by whatever you need. Example: if, as you say, 145 is 85% then divide 145 by 85 to get one percent; then multiply by 15 to get the other part. If you want to know the hundred percent just add them together. If you start with 100%, just divide it by ten then multiply by whatever percentage you need. Simple no? Cheques may be made payable to Bigroryg * * * Sincerely, SDStaff hopeful ---
**Author:** ![AWB](https://avatars.discourse-cdn.com/v4/letter/a/bb73d2/32.png) [@AWB](https://boards.straightdope.com/u/AWB)\ **Post date:** [August 27, 1999, 5:17am UTC](https://boards.straightdope.com/t/innumerate-needs-formula-simple-help/2867/7 "1999-08-27T05:17:00Z")
\*Stoidela: I need the formula to arrive at the following. N is 85% of \_\_\_\_\_ (number)? Sample: I receive $145 from you. You tell me that this is my percentage, which we both know is 85% of the total number. You receive 15% of the total number. What is the total number? What is your 15%? And what is the formula I use to arrive at these numbers? (I need it frequently, and I never remember it. I’m an idiot at math.)\* Let X be the total number, and N is your share, the 85%. 85% \* X = N 0.85 \* X = $145.00 dividing by 0.85 ``` $145.00 ``` X = --------- 0.85 X = 170.59 _I would be forever in your debt…_ Just e-Mail me your Visa/MC number. 🙂 ---
**Author:** ![Stoid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/stoid/32/272_2.png) [@Stoid](https://boards.straightdope.com/u/Stoid)\ **Post date:** [August 26, 1999, 6:02pm UTC](https://boards.straightdope.com/t/innumerate-needs-formula-simple-help/2867/8 "1999-08-26T18:02:00Z")
Well, gee, I can’t be in EVERYBODY’s debt. Since Nickrz answered me first, via e-mail ince the board was not working, I guess my debt is to him. But I do appreciate the help! Stoid ---
**Author:** ![TheIncredibleHolg](https://avatars.discourse-cdn.com/v4/letter/t/8797f3/32.png) [@TheIncredibleHolg](https://boards.straightdope.com/u/TheIncredibleHolg)\ **Post date:** [August 27, 1999, 6:50am UTC](https://boards.straightdope.com/t/innumerate-needs-formula-simple-help/2867/9 "1999-08-27T06:50:00Z")
> [@](#): > > Since Nickrz answered me first, via e-mail ince the board was not working, I guess my debt is to him. No fair, Nickrz! Especially since the rest of us don’t have his e-mail address. Shame on you! ---
**Author:** ![HeadlessCow](https://avatars.discourse-cdn.com/v4/letter/h/db5fbb/32.png) [@HeadlessCow](https://boards.straightdope.com/u/HeadlessCow)\ **Post date:** [August 27, 1999, 8:30pm UTC](https://boards.straightdope.com/t/innumerate-needs-formula-simple-help/2867/10 "1999-08-27T20:30:00Z")
I’d like a chance to have Stoidela indebted to me. So I’ll tell my story of trying to help her. Someone (Nickrz) posted the answer first to the board but posted the wrong answer. When I tryed to reply and berate him for screwing up Stoidela I found that the board wasn’t working, so I saved my reply and was prepared to post it at my first chance, but now lots of other people have answered and Nickrz incorrect post is nowhere to be found.