Answer
When driving more than 100 miles in a day, Basic Rental charges less (gives a better deal).
Work Step by Step
Let $ x $ be the number of miles driven in a day.
Basic Rental charges $\quad 0.2x+50$
Continental charges $\quad 0.5x+20$
We want x for which Basic charges less.
$ 0.2x+50 \lt 0.5x+20\qquad $ ... add $-0.2x-20$
$ 30 \lt 0.3x\qquad $ ... multiply with $\displaystyle \frac{10}{3}$
$100 \lt x $
or, $ x\gt 100$
Thus, when driving more than 100 miles in a day, Basic Rental charges less (gives a better deal).
