Isn’t there a standard reply containing utility functions? You should buy N tickets where N is the solution to p(win | N tickets) * U(jackpot) + U(-N dollars) is maximal. Assuming the usual diminishing marginal utility of money and that U(jackpot) * p(win | 1 ticket) > -U($-1), a unique solution should exist for N > 0.
Second attempt (thanks janos):
Isn’t there a standard reply containing utility functions? You should buy N tickets where N is the solution to p(win | N tickets) * U(jackpot) + U(-N dollars) is maximal. Assuming the usual diminishing marginal utility of money and that U(jackpot) * p(win | 1 ticket) > -U($-1), a unique solution should exist for N > 0.