[tex]42 \frac{1}{2} + 37 \frac{4}{5} [/tex]
[tex]42 \frac{5}{10} + 37 \frac{8}{10} [/tex]
[tex] \frac{5}{10} + \frac{8}{10} = \frac{13}{10} = 1 \frac{3}{10} [/tex]
[tex]79 + 1 \frac{3}{10} = 80 \frac{3}{10} [/tex]
[tex]80 \frac{3}{10} \: \:miles \: or \: 80.3 \: miles[/tex]
//
Just double check that I did the right calculations
