GRE数学考点精编一:At Least Once(1)

At Least Once

  At Least Once

  If probability of an event happening is p, then the probability that the event happens at least once in n trials is 1-(1-p)∧n.

  Example:

  To understand the equation follow these steps:

  1.The probability of the event not happening is 1-p.

  2.The probability it won't happen n-times in a row is (1-p)∧n.

  3.Probability it will happen at least once is 1-(1-p)∧n.