For this problem, you best start with calculating how many miles they drive in 1 hour, by dividing 192 by 4.5, which equals 42.666. You then multiply this by 3 to get the distance after 3 hours.
To prevent rounding errors, you can put this all in one equation:
[tex]\frac{192}{4.5} \times {3} =128[/tex]
So answer C looks like the right one.
