Step-by-step explanation:
Total tickets = 500
Tickets number bought by David = 5, 6, 7 and 8
Number of tickets bought by David = 4
Remaining ticket = 500 - Number of tickets bought by David
Remaining ticket = 500 - 4
Remaining ticket = 496
Odds in favour of an event = success for the event/ failures for the event
success for winning the raffle = Number of tickets bought by David = 4
failures for winning the raffle = Remaining ticket = 496