An 11/2 bet means that for every £2 you stake, you stand to win £11 in profit, plus your original stake back. So, if you bet £2 on 11/2 odds, your total return would be £13 (£11 profit + £2 stake). If you bet £10, your return would be £65 (£55 profit + £10 stake). This fractional odds format is commonly used in the UK for horse racing and other sports betting.