3
$\begingroup$

If I have the following two different values for x:

x = 0.022

x = 0.020

And, if I want to calculate the percentage of the difference (change) in x, will it be?

---> 0.022 - 0.020 = 0.002

---> 0.002 x 100% = 0.2%?

And, should the percentage of the difference be always positive?

Thanks.

1 Answers 1

6

I presume you have an initial value for $x$, and then a later value for $x$, and you want to calculate what percent change you have from the initial value of $x$.

So say you have two values $x_1=.02$ and $x_2=.022$. So as you've calculated, the increase in going from $x_1$ to $x_2$ is $.022-.02=.002$. But $.002/.02=.1$, so there has been a $10\%$ increase in $x$ from the initial value.

The percentage of the difference won't always be positive if your second value of $x$ is smaller than the first. For example, if instead $x_1=.022$ and $x_2=.02$, then the change is $-.002/.022\approx-9.09\%$.

In general, to find the percentage of change, you can use the formula $ \frac{x_f-x_i}{x_i}\cdot 100\% $ where $x_i$ is your initial value of $x$, and $x_f$ is your final value of $x$.

  • 1
    The formula should always include the Absolute Value of the Denominator!2013-04-01