Answer:
A. "an arithmetic sequence with a common difference (d) of -6."
B. 33 hours
C. 
D. See below
Step-by-step explanation:
A.
Since the sequence lessens by 6, this is an arithmetic sequence with a common difference (d) of -6.
B.
The formula for term of arithmetic sequence is:

Wher a_1 is the first term and d is the common difference. Since we want to find after 33 weeks, we plug in 33 into n:

She will have left 33 hours
C.
We will use the arithmetic sequence term formula written above, that is:

THis gives us the amount of hours left after a certain number of weeks.
D.
We plug in 40 into n and find the hours left:

THis term is NEGATIVE, which means that Greta will not have to work 40 weeks to fulfill the target of 225 hours. She needs to work less.