A set of 3 cards, spelling the word ADD, are placed face down on the table. Determine [tex]$P(A, D)$[/tex] if two cards are randomly selected with replacement.

A. [tex]\frac{1}{3}[/tex]
B. [tex]\frac{2}{3}[/tex]
C. [tex]\frac{2}{9}[/tex]
D. [tex]\frac{4}{9}[/tex]



Answer :

To determine the probability [tex]\( P(A, D) \)[/tex] of drawing an 'A' first and a 'D' second when two cards are drawn with replacement, let's analyze the problem step-by-step.

1. Identify the individual probabilities:
- The set of cards consists of the letters A, D, and D.
- There are 3 cards in total.

Step 1: Calculate the probability of drawing an 'A' (denoted as [tex]\( P(A) \)[/tex]):
- There is 1 'A' card out of 3 cards.
[tex]\[ P(A) = \frac{1}{3} \][/tex]

Step 2: Calculate the probability of drawing a 'D' (denoted as [tex]\( P(D) \)[/tex]):
- There are 2 'D' cards out of 3 cards.
[tex]\[ P(D) = \frac{2}{3} \][/tex]

2. Since the cards are replaced, these events are independent:
- This means the probability of drawing 'A' first and then drawing 'D' can be found by multiplying the individual probabilities.

3. Calculate the combined probability [tex]\( P(A, D) \)[/tex]:
- The probability of drawing 'A' first and then 'D' second is:
[tex]\[ P(A \text{ then } D) = P(A) \times P(D) \][/tex]
- Now, substitute the individual probabilities we calculated:
[tex]\[ P(A \text{ then } D) = \frac{1}{3} \times \frac{2}{3} = \frac{1 \times 2}{3 \times 3} = \frac{2}{9} \][/tex]

Therefore, the probability [tex]\( P(A, D) \)[/tex] of drawing 'A' first and 'D' second with replacement is [tex]\( \frac{2}{9} \)[/tex].

So, the correct answer is [tex]\( \frac{2}{9} \)[/tex].