A-LevelMathematicsProbability and statisticsOct/Nov 2025Paper 5 Q27 Marks
Kayla has a bag containing 3 red marbles, 1 blue marble and 2 green marbles. She selects one marble from the bag at random and does not replace it in the bag. She repeats this process until she obtains a green marble. The random variable X is the number of marbles that she needs to select until she obtains a green marble.
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