In order to find this amount you need to find how much he makes in each month individually. We'll start with month one where he sold $13,500 worth of software. Since that number is under $20,000 we know that he makes 10%. So to find his earnings, we simply multiply the told sold by the percentage.
$13,500 * 10% = $1,350
Now we need to find the amount for month two. Since he sold $26,700, which is more than $20,000 we know that he gets the 15% of the amount sold. Similarly to last time, we'll multiply the two together.
$26,700 * 15% = $4,005
Now you can combine the two of them to find the overall amount.
