Q$\mathrm{.}1$ If you rent a car you can

$(1)$ return it with a full gas tank,

$(2)$ return it without filling it and pay $$1\mathrm{.}12/$liter$.$

The local price is $$0\mathrm{.}97/$liter for gasoline, and you expect this car to get $8\mathrm{.}5$ L$/100$ km$.$

The car has a $76-$liter tank. What choice should you make if you expect to drive

$($a$)280$ km$?$

$($b$)380$ km$?$

$($c$)750$ km$?$

$($d$)$ How do your answers change if stopping at the filling station takes $20$ minutes and

your time is worth $$28/$hour$?$