A bag of marbles contains 3 red, 4 blue, and 5 green marbles. Assuming you are drawing without replacement, find the probability of drawing a green marble and then a red marble.

Because the problem specifies no replacement, these are dependent events. There are 12 marbles in total, 5 of which are green. Therefore, you can draw 5 from 12 on the first draw. This leaves 11 marbles in the bag, 3 of which are red. Therefore, you can draw 3 from 11 on the second draw.

The probability of drawing a green marble and then a red marble is or about 11%.

 

Read pages 182-183 Example 1 in your textbook, Principles of Mathematics 12 .

Complete the Reflecting questions on page 183 (A - E) for more practice with dependent events.

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