Probability of Winning Raffle with Multiple Tickets

Question

A reliable organization is sponsoring a raffle where "tickets" are purchased with points earned, The sponsor states that the probability of winning are 1 in 6,200,000,000. Each "entry ticket" costs 10,000 points. With a bank of 2,100,000,000, there is enough for 210,000 entry tickets. What would the probability be of winning the grand prize if 210,000 entry tickets are submitted? (The grand prize is cash).

Answer 1

this is actually pretty straightforward! so we have a probability of winning of 1/6,200,000,000 and we have 210,000 tickets. Since each ticket is one chance, the result is simply that our chance of winning is now 210,000/6,200,000,000, or 21/620,000 which is just a little less than a 1 in 30,000 chance.