Let me restate what Dan correctly said:
1). $3.10 for each $1 wagered.
2). $2 to win = $3.10 for each $1 bet = $6.20
3). The $2.00 bet you made is returned so you have $6.20 + $2.00 = $8.20 collected at the window if the horse wins.
When I was a rookie player, it took me a while to figure this out. :mj03: