Text: If the Powerball jackpot is worth $50 million and less than $50 million worth of tickets have been sold, then the odds are favorable--and rational betters will rush in to buy tickets, guaranteeing that at least $50 million in tickets will be sold.
Entailment: With the right circumstances it can be guaranteed that a certain number of lotto tickets will be sold.
Contradiction: Powerball jackpots are never worth more than $1 US.