Answer:
Chau drove 139 miles
Explanation:
Knowing how much Chau spent at the end makes the question much much easier. So what you want to do is take of the base fee ($20.99) off the final amount he had to pay.
$130.80 - $20.99 = $109.81
Now you divide $109.81 by the additional charge ($0.79)
Change the divisor (0.79) to a whole number by moving the decimal point 2 places to the right. Then move the decimal point in the dividend (109.81) the same, 2 places to the right.
We then have the equations:
10981 ÷ 79 = 139.000
and therefore:
109.81 ÷ 0.79 = 139.000
Chau drove 139 miles.