A Lucky 15 is 15 bets based around four selections, basically a Yankee with four singles as well. If there is only one winner, it is paid out at double odds.
A fifteen-bet wager consisting of a Yankee (six doubles, four trebles and one four-horse accumulator) plus singles on each of the four selections. If just one of your selections wins, most bookmakers pay at double the winning odds.
a combination bet consisting of 15 bets from 4 selections. A lucky 15 contains 4 singles, 6 doubles, 4 trebles and a four-fold. In a lucky 15 if you luck out and only have one winner then it is paid at double odds and all 4 winners gets a 10% bonus.