a)
i) C(n)=42n
ii)C(n,x)=15n+0.25x
b)She plans to drive a total of 600 Km, therefore: x=600
Budget: C(n)=42n
Deluxe: C(n,x)=15n +0.25(600)=15n+150
Cost of Budget< Cost of Deluxe
42n<15n+150
42n-15n<150
27n<150
n<150/27
n<5.5 ⇒n<5
Answer: The maximum number of days would be 5 days.
