Answer:
when the distance driven per day is 100 miles
Explanation:
Start by writing an equation for the daily charge of each company
Let's call p(x) what the primo car rental charges per mile "x", and let's call u(x) what ultimo rental charges;
p(x) = 24 + 0.4 x
u(x) = 38 + 0.9 x
when would u(x) be twice the p(x) charge?
u(x) = 2 p(x)
38 + 0.9 x = 48 + 0.8 x
0.9 x - 0.8 x = 48 - 38
0.1 x = 10
x = 100
so, such happens when the distance driven per day is 100 miles