Question

Abby is touring china for four days. The car rental is $38.15 per day plus 12 1/2 cents per mile. If Abby drives 380.5 miles, how much does she owe the rental company ?

Answer 1

The car rental is 38.15 + 12 1/2 per mile or 

$\bf \textit{rental function R(x) then is } \\\\ R(m)=38.15+12\frac{1}{2}m\implies R(m)=38.15+\cfrac{25}{2}m \\\\ -----------------------------\\\\ \textit{she drove 380.5 miles}\implies m=380.5\\\\ -----------------------------\\\\ R(380.5)=38.15+\cfrac{25}{2}(380.5)\impliedby \textit{she owes that much}$

now, we're assuming she drove that in 1day, thus she's only getting charged 38.15, for 1 day :)