A lottery sells 10,000 tickets and awards 10 prizes. If you buy one ticket, what is the probability that you do not win a prize?

Difficulty: Easy

Correct Answer: 999/1000

Explanation:


Introduction / Context:
In a finite uniform lottery, the probability of winning equals the number of prize tickets divided by total tickets. The probability of not winning is the complement.



Given Data / Assumptions:

  • Total tickets = 10,000.
  • Prizes = 10.
  • One ticket purchased; each ticket is equally likely to be drawn as a prize.


Concept / Approach:
P(no prize) = 1 − P(prize) = 1 − (prize tickets / total tickets).



Step-by-Step Solution:
P(prize) = 10 / 10000 = 1 / 1000.Therefore, P(no prize) = 1 − 1/1000 = 999/1000.



Verification / Alternative check:
Non-prize tickets = 10000 − 10 = 9990. For one ticket chosen uniformly, P(no prize) = 9990/10000 = 999/1000 after simplification.



Why Other Options Are Wrong:
9999/10000 would correspond to 1 prize; 9/10 ignores the precise counts; 1/1000 is P(win), not P(no win).



Common Pitfalls:
Mixing up the probability of winning with not winning; not simplifying to lowest terms.



Final Answer:
999/1000

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