She would need to make an 89 on her last test. I hope this helped ^^
What I did is I put a made a list in ascending order (Least to greatest). Next, I added a number starting from 80 and then counted up. I added every number together and divided it by 5 every time I changed the number. Finally I got to the number 89 and it totaled to be 85.
Answer:
+10
Step-by-step explanation:
The law of integers states that a negative number divided by a negative integer would result in a positive integer, therefore;
-40 / -4 = 10
Hope this helps!
You can download answer here
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The function for the amount saved if they purchase a used drone rather than a new drone from Jim's store is f(x) = 0.45x
He sells used drones at 70% of the price (x).
So, the selling price of a used drone is:

Express percentage as decimal


Also, he sells new drones at 15% more of the price (x).
So, the selling price of a new drone is:

Express percentage as decimal



The amount saved is the difference between the prices of the drones.
So, we have:

This gives

Subtract

Express as a function

Hence, the function for the amount saved is f(x) = 0.45x
Read more about proportions at:
brainly.com/question/13114933