Answer:
y = 5
Step-by-step explanation:
That "+5" elevates the graph of this cosine function 5 units above the x axis, and thus the "midline" you wanted is y = 5.
First, we count how far reached the Nell:
3,5 * 16 = 56 miles
Secondly, we count how far reached the Kristin:
3,5 * 18 = 63 miles
Now we expect the difference in the distance between them:
63 - 56 = 7 miles
The results that Kristin about seven miles driven more than Nell.