i have a weekly competition where any number of entrants may turn up. if up to 23 play then there are three prizes (50%,30% and 20%)

If 24 to 32 play there are four prizes (40%.30%.20%.10%)

33 to 38 five prizes £25 max £20max £15max £10max £6 max

The number of payers is automatically counted when the scores are added and the entry fee is £2