Complex sentence: In one example, a bookmaker has offered odds and attracted bets that make the result irrelevant; in this case the implied probabilities (probabilities of each horse winning) will add up to a number greater than 1.
Split into simpler sentences: In one example, a bookmaker has offered odds and attracted bets that make the result irrelevant. The implied probabilities, i.e. probability of each horse winning, add up to a number greater than 1.