 A Dutch or an arb is profitable if the sum of the reciprocals of the decimal odds of each selection is less than 1, and each bet is sized such that the payout in each outcome are the same.Additionally, the profitability of a Dutch/arb can be expressed as 1-R, where R is the sum of the reciprocals.In practice, bookmakers will always ensure that R is comfortably greater than 1, to generate a profit for themselves and to negate the effect of any slight arbitrage possibilities between different bookmakers.