Answer:
4/3
Explanation:
Rate of change is also known as slope.
To find slope, you have to find the change in y divided by the change in x.
y2-y1 / x2-x1
The variable y in this situation is the number of sodas.
The variable x in this situation is the total cost.
28 - 24 / 21 - 18
= 4 / 3
The rate of change in this problem is 4/3.