D is the answer
Multiply 15 times 30 and divide by 2.25
Answer:

Step-by-step explanation:
The explicit formula for a geometric sequence:

- n-th term
- first term
- common ratio

We have

The common ratio:

<h2>It's not a geometric sequence.</h2>
If
then the common ratio is 
Put to the explicit formula:

Put
and solve for <em>n </em>:


Answer:
Step-by-step explanation:
9. discount is 9 dollars. sale price is 36 dollars
10. discount is 135 dollars sale price is 315
11. discount is 7.20 dollars, sale price is 41.80
12. discount is 37.50. sale price is 112.50
13. discount is 590. sale price is 870
14. discount is 42. sales price is 42
15. discount is 32.50. sales price is 292.50
16. discount is 29.75. sales price is 56.25
17. The similarities is that there's a difference in the original price, usually in a percentage. The difference is that a markup is a increase whereas a discount is a decrease
C. 20% because 15 goes into 75 5 times, and to find the percentage you would divide 100 by that number, 5, to get 20. So he has gone 20%