College

A box contains three cards. On one card, there is a question mark (Q), on another card, there is a pear (P), and on the third card, there is a triangle (T). Two cards are to be selected at random with replacement. Complete parts (1) through (3) below.

1. **List the sample space.** Choose the correct answer below.
- A. QP, PT, TQ
- B. QQ, QP, QT, PQ, PP, PT, TQ, TP, TT
- C. [tex]$QP, QT, PQ, PT, TQ, TP$[/tex]
- D. [tex]$QQ, QP, QT, TQ, TP, \Pi T$[/tex]

2. **Determine the probability that two triangles are selected.**

The probability is [tex]$\frac{1}{9}$[/tex]. (Simplify your answer.)

3. **Determine the probability that a card containing a pear and then a card containing a triangle are selected.**

The probability is [tex]$\square$[/tex]. (Simplify your answer.)

Answer :

Sure! Let's go through the solution step by step for the given problem:

a) List the sample space.

When we select two cards with replacement from the box, each card can appear in both positions. The cards are marked with a question mark (Q), a pear (P), and a triangle (T). Here’s how you list all the possible outcomes:

1. First card Q, Second card Q - (Q, Q)
2. First card Q, Second card P - (Q, P)
3. First card Q, Second card T - (Q, T)
4. First card P, Second card Q - (P, Q)
5. First card P, Second card P - (P, P)
6. First card P, Second card T - (P, T)
7. First card T, Second card Q - (T, Q)
8. First card T, Second card P - (T, P)
9. First card T, Second card T - (T, T)

Therefore, the sample space is:
[('Q', 'Q'), ('Q', 'P'), ('Q', 'T'), ('P', 'Q'), ('P', 'P'), ('P', 'T'), ('T', 'Q'), ('T', 'P'), ('T', 'T')].

b) Choose the correct answer for the sample space:

The correct answer that matches the above list is option B: QQ, QP, QT, PQ, PP, PT, TQ, TP, TT.

c) Determine the probability that two triangles are selected.

From the sample space, we see that there is only one outcome where both cards are triangles: (T, T).

The probability of this happening is calculated by dividing the number of favorable outcomes by the total number of outcomes in the sample space:

- Number of favorable outcomes (T, T) = 1
- Total number of outcomes = 9

So, the probability is [tex]\( \frac{1}{9} \)[/tex].

d) Determine the probability that a card containing a pear and then a card containing a triangle are selected.

From the sample space, the outcome where a pear is followed by a triangle is (P, T).

- Number of favorable outcomes (P, T) = 1
- Total number of outcomes = 9

Thus, the probability is also [tex]\( \frac{1}{9} \)[/tex].

By breaking down the problem in this way, it’s clear how the probabilities are derived from the sample space of two-card selections with replacement.