[tex]\begin{array}{ccccccc}580miles&-&20gallons\\/:20&&/:20\\29miles&-&1gallon\\58miles&-&2gallons\\87miles&-&3gallons\\116miles&-&4gallons\\145miles&-&5gallons\\174miles&-&6gallons\\203miles&-&7gallons\\232miles&-&8gallons\\261miles&-&9gallons\\290miles&-&10gallons\end{array}[/tex]