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September 4th, 2018, 08:49 PM  #1 
Newbie Joined: Sep 2018 From: toronto Posts: 2 Thanks: 0  simple maths problem driving me nuts.
if 100x = 1.1 and 0x=0.9 what is the value of x? I need the answer to be written out into a formula as I'm trying to code an algorithm into a sliding function that increases a number by 10% when it's at 100, and decreases it by 10% when at 0. Last edited by skipjack; September 4th, 2018 at 09:42 PM. 
September 4th, 2018, 09:48 PM  #2 
Senior Member Joined: Sep 2015 From: USA Posts: 2,311 Thanks: 1223 
$0x = 0$ for all $x$ $10\% \text{ of }0 \text{ is }0$ maybe rethink exactly what it is you are trying to do. 
September 4th, 2018, 09:58 PM  #3 
Global Moderator Joined: Dec 2006 Posts: 20,285 Thanks: 1967 
Would an increase of (0.2x  10)% be okay? That's 10% for x = 0 and 10% for x = 100. It would change the number y to (0.002x + 0.9)y, which is 0.9y for x = 0 and 1.1y for x = 100. 
September 5th, 2018, 07:41 AM  #4 
Newbie Joined: Sep 2018 From: toronto Posts: 2 Thanks: 0 
thank you so much skipjack! could you point me towards where I can learn more about these kind of problems. I imagine you did: y= the difference between the two points y= 1.10.9 y= 0.2 x= a number between 0 and 100 so (yx10)%, but how did you get the 10? 
September 5th, 2018, 10:08 AM  #5 
Global Moderator Joined: Dec 2006 Posts: 20,285 Thanks: 1967 
I didn't say (yx10)%. The change is (0.2x  10)% for any y. Putting x = 0 gives 10%, and putting x = 100 gives 10%, as requested.


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