We can convert that 30% into a decimal, as: 0.3 (That's 30/100)
Now, we can multiply this 0.3 by any quantity that we want to calculate 30% from.
For example, let's take Justin's commission:
![2425\cdot0.3=727.5](https://img.qammunity.org/2023/formulas/mathematics/high-school/gzsal01n339mv6k9hxym9356w77swngu31.png)
Adding this to his base salary,
![450+727.5=1177.5](https://img.qammunity.org/2023/formulas/mathematics/high-school/6oadko1i51mzto5ckpp2v73uakntb9x6vu.png)
We can conclude that Justin's paycheck for the week would be $1,117.5
Similarly, the expression for Justin's paycheck in a week were he made x dollars in sales is:
![0.3x+450](https://img.qammunity.org/2023/formulas/mathematics/high-school/qfjt8yrndifx6fw7xxkbvbvmvyuaqot4vr.png)