Answer:
$25.68
Sales Price:
In order to find the sales price we need to find what 20% off of $30 is. 20% off is 80% of the original price so we'll use 80% instead. Now what we need to do to find 80% of $30 is we need to multiply $30 by 0.8. When you're converting precents to decimals you move the decimal place over 2 spots like this: 38.0% = 0.38. Okay, now that we've figured that out we can do the multiplication:
$30 · 0.8 = $24
Sales Tax:
Now there are 2 ways to go from here:
1. Multiply $24 by 7% then add it to $24
This is the first solution to come to mind but is inefficient
2. Multiply $24 by 107%
You skip the second step by adding $24 in the percent (since $24 is 100% in this case).
Either way you come to the conclusion of $25.68
Hope this helps!