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drawing_marbles.md

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Link to task: Drawing Marbles

Task:

A bag contains 3 red marbles and 4 blue marbles. Then, 2 marbles are drawn from the bag, at random, without replacement. If the first marble drawn is red, what is the probability that the second marble is blue?

Solution:

Total marbles in bag: 3 Red + 4 Blue = 7

First marble drawn is Red. Now, we have only 6 marbles remaining to choose our second marble from.

  • Total cases: C(6, 1) = 6

  • Favourable cases:

    Since we want our second marble to be Blue, we have only 4 marbles to choose from.

    Therefore, total favourable cases: C(4, 1) = 4

Probability that the second marble is blue: C(4, 1) / C(6, 1) = 4 / 6 = 2/3