Question on Triangular Arbitrage with Bid-Ask Spread?

Homework 1 on Triangular Arbitrage with Bid-Ask Spread Suppose Citibank's quote: $1.5445 1.5460/ Barclay's quote: $1.9443-1.9453 / Dresdner's quote: 1.2789 - 1.2799/ Cross-rate between Citibank and Barclay should be to the actual Dresdner quote of1.2789 / 1.2589 / , compared Is triangular arbitrage possible if an investor starts with follows the following two strategies independently? 1 million and (a) Euros to Dollars to Pounds to Euros. (b) Euros to Pounds to Dollars to Euros. If there are arbitrage gains or losses in either case, how much