I think the answer is D. 66
The correct answer is C) -15.
Anyways, I hope you have a wonderful evening :)
For this case we have the following arithmetic sequence:
![a_ {n} = 15 + 5 (n-1)](https://tex.z-dn.net/?f=a_%20%7Bn%7D%20%3D%2015%20%2B%205%20%28n-1%29)
To write in function form, we apply distributive property to the terms within parentheses:
![f (n) = 15 + 5n-5](https://tex.z-dn.net/?f=f%20%28n%29%20%3D%2015%20%2B%205n-5)
Different signs are subtracted and the major sign is placed.
We simplify:
![f (n) = 5n + 10](https://tex.z-dn.net/?f=f%20%28n%29%20%3D%205n%20%2B%2010)
Answer:
![f (n) = 5n + 10](https://tex.z-dn.net/?f=f%20%28n%29%20%3D%205n%20%2B%2010)
Option C
3/4 of a pound is half of 1.5 pounds ( 3/4 + 3/4 = 1.5)
3.60 / 2 = $1.80
it will cost $1.80 for 3/4 of a pound