Question

A bag contains 6 white marbles, 5 red

marbles, 19 marbles of other colors. Find the probability of choosing a white marble and then a red marble if you replace the first marble before choosing the second marble.

Answer 1

1/30

Explanation:

6 white marbles

5 red marbles

+ 19 marbles of other colors

-----------------------------------------------

30 marbles in total

First drawing:

p(white) = (number of white marbles)/(total number of marbles)

p(white) = 6/30 = 1/5

Second drawing:

Since the first marble is replaced, there are still 30 marbles in the bag.

p(red) = (number of red marbles)/(total number of marbles)

p(red) = 5/30 = 1/6

The two drawings are independent events, so the overall probability of the two events is the product of the individual probabilities.

p(white then red) = p(white) × p(red)

p(white then red) = 1/5 × 1/6

p(white then red) = 1/30