emarinich wrote:

probability of selecting a red ball and then a white ball on 2 successive draws if the ball is returned to the bag after the first draw:

P(red) * P(white)

(3/9) * (2/9) = 6/81 or 2/27

answer choice A.

Oh yeah... That's exactly why I posted this

OA

D
[quote]

Your Answer : A

Actual Answer : D

Explanation

Probability of a desired outcome = Number of favourable outcomes / Total number of possible outcomes.

There are a total of 9 balls in the bag.

3 out of the total 9 balls are red.

Probability of drawing a red ball = 3/9

The one ball that is drawn is returned back into the bag and another ball is drawn.

Now, 2 out of the total 9 balls are white.

Probability of drawing a white ball = 2/9.

Hence probability of drawing a red and a white ball in two successive draws = 3/9 * 2/9 = 1/3 * 2/9 = 2/27.

The order in which the ball is drawn is not specified. It could be a red ball first or it could be a white ball first.

Hence the probability will be 2/27 + 2/27 = 4/27.

Hence (D) is the correct answer.

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