Hello and Good Morning/Afternoon
<u>Let's take this problem step by step</u>:
<u>To find the rate of change is essentially like finding a line's slope</u>:
⇒ the <em>x-values</em> are the <em>number of sodas</em>
⇒ the<em> y-values </em>are the <em>total costs</em>
<em> ⇒ choose</em> two sets of coordinates and find the slope
<u>Let's put that into action</u>
⇒ (24, 18)
⇒ (28, 21)

<u>Since the rate of change is total cost over number of sodas</u>
⇒ <em>unit is '</em>total cost/number of sodas'
<u>Answer: 3/4 total cost/number of sodas</u>
<u></u>
Hope that helps!
#LearnwithBrainly
<u><em /></u>