8 Is your answer so option A
Answer:
The answert is "$0.007 / bottle".
Step-by-step explanation:
Please find the complete question in the attachment file.

The average income:

The change rate on the average revenue:

when 81 bottles were produced
, then the rate of change in average revenue
The average income is decreasing at rate = $0.007 / bottle
We need to multiply 4/5 by 4 5/8. We change 4 5/8 into a fraction to do the multiplication.
4/5 * 4 5/8 =
= 4/5 * 37/8
= 148/40
= 37/10
= 3 7/10
Answer: Sara's sister is 3 7/10 ft tall.