Chance of winning in a raffle

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A raffle consists of 10 sheets with 10 numbers (1 to 10) on each sheet i.e. 100 chances in total. The draw is done by first selecting a sheet at random and then selecting the winning number out of the 10 from that sheet. If a person buys 10 tickets:

  • puts his name on all 10 places on 1 sheet then the chances of winning is 1/10 x 10/10 = 10%
  • puts his name once on each sheet then the chances of winning is 10/10 x 1/10 = 10%

I need to know what the chance of winning is if he randomly place his name 10 times across the ten sheets.

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This is a binomial random variable problem.

Use the theorem nCk (p)^k (1-p)^(n-k)

Where p is probability of success.