SOLUTION: Hi, I had just learned about probability, premutaions and combinations, but I am a bit confused with everything. I find it difficult to understand when to use which and how to use

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Question 908984: Hi, I had just learned about probability, premutaions and combinations, but I am a bit confused with everything. I find it difficult to understand when to use which and how to use it. So I need help in a question I was thinking of...
The question: Suppose I am one of 75 people who are contestents to win a free traveling ticket. There are 25 winning places. What is the probability of me being chosen as a winner.
I don't think we should use a premutation, but I can;t about anything else about how to solve this question.
Thanks in advance for your help.
Answer by rothauserc(4718) (Show Source):
You can put this solution on YOUR website!
there are 75 contestants and 25 winning places, therefore in the first drawing you have 25/75 = 1/3, which means a one in three chance on the first draw
assuming you keep having drawings until all winning places have been determined
(1/3)+(24/74)+(23/73)+(22/72)+(21/71)+(20/70)+(19/69)+(18/68)+(17/67)+(16/66)+(15/65)+(14/64)+(13/63)+(12/62)+(11/61)+(10/60)+(9/59)+(8/59)+(7/58)+(6/57)+(5/57)+(4/56)+(3/55)+(2/54)+(1/53) = your probability of winning one of the winning places