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CAIE A Level Mathematics 9709 · Discrete random variables

Discrete random variables: calculation question

3 marksChallenge

Each time a machine is switched on it starts correctly with probability 90%90\%, independently of every other attempt. The random variable XX is the number of the attempt on which it first starts correctly.

  1. (a)

    Find P(X>2)\mathrm{P}(X > 2).

    [3]

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