My Math Forum  

Go Back   My Math Forum > High School Math Forum > Algebra

Algebra Pre-Algebra and Basic Algebra Math Forum


Reply
 
LinkBack Thread Tools Display Modes
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.
thenumberfool is offline  
 
September 4th, 2018, 09:48 PM   #2
Senior Member
 
romsek's Avatar
 
Joined: Sep 2015
From: USA

Posts: 2,174
Thanks: 1142

$0x = 0$ for all $x$

$10\% \text{ of }0 \text{ is }0$

maybe rethink exactly what it is you are trying to do.
romsek is offline  
September 4th, 2018, 09:58 PM   #3
Global Moderator
 
Joined: Dec 2006

Posts: 19,882
Thanks: 1835

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.
skipjack is offline  
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= 1.1-0.9
y= 0.2

x= a number between 0 and 100

so (yx-10)%, but how did you get the -10?
thenumberfool is offline  
September 5th, 2018, 10:08 AM   #5
Global Moderator
 
Joined: Dec 2006

Posts: 19,882
Thanks: 1835

I didn't say (yx-10)%. The change is (0.2x - 10)% for any y. Putting x = 0 gives -10%, and putting x = 100 gives 10%, as requested.
skipjack is offline  
Reply

  My Math Forum > High School Math Forum > Algebra

Tags
driving, maths, nuts, problem, simple



Thread Tools
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
Maths question. Please answer it is driving me crazy mavi1 New Users 1 September 16th, 2017 10:36 AM
The most simple problem is driving me insane. wvu1811 Algebra 3 October 20th, 2013 08:26 AM
Simple Maths problem? pupbrown Algebra 5 May 4th, 2011 02:59 PM
Please help this problem is driving me nuts!!! sophieT66 Number Theory 4 October 7th, 2010 10:19 AM
Simple Maths problem? pupbrown Number Theory 5 December 31st, 1969 04:00 PM





Copyright © 2018 My Math Forum. All rights reserved.