Answer:
$314
Step-by-step explanation:
1. She has 18 demonstrations, so she got $10 for each of the first 10 to equal $100.
2. She got 8 demonstrations after those 10. For each of those, she gets $15.50. $15.50x8=$124.
3. She had 6 sales. Every sale is $15. $15x6=$90
4. $100+$124+$90 =$314