Suppose the following bilateral spot exchange rates are being quoted for the Danish krone (DKK), the US dollar (US$) and the euro (€):
US$/€ = 1.5
DKK/€ = 7.0
DKK/$ = 5.0
If you start with 100€, the most you could end up with in a single round of triangular arbitrage would be...
Convert €100 to $150 (1.5*100) to DKK 750 (150*5) and back to €107.14 (750/7).