Select the correct answer.

Chris is playing a game with his father using a six-sided die. What is the expected value per roll that Chris will get if his father agrees to give him [tex]$2 multiplied by every even number rolled and $[/tex]1 multiplied by every odd number rolled?

A. [tex]$1.50
B. $[/tex]4.50
C. [tex]$5.50
D. $[/tex]10.50
E. $12.00



Answer :

To determine the expected value per roll that Chris will receive in the game, we need to analyze each possible outcome on the six-sided die and the corresponding reward based on whether the rolled number is even or odd.

A six-sided die has the faces: {1, 2, 3, 4, 5, 6}. Each face has an equal probability of 1/6 of being rolled.

Let's break it down face-by-face:

1. Face 1: It's an odd number.
- Reward: [tex]$1 1 = $[/tex]1

2. Face 2: It's an even number.
- Reward: [tex]$2
2 = $[/tex]4

3. Face 3: It's an odd number.
- Reward: [tex]$1 3 = $[/tex]3

4. Face 4: It's an even number.
- Reward: [tex]$2
4 = $[/tex]8

5. Face 5: It's an odd number.
- Reward: [tex]$1 5 = $[/tex]5

6. Face 6: It's an even number.
- Reward: [tex]$2
6 = $[/tex]12

Next, calculate the expected value by summing the rewards, each multiplied by the probability of rolling that face (1/6):

[tex]\[ \text{Expected Value} = \left(\frac{1}{6} \times 1\right) + \left(\frac{1}{6} \times 4\right) + \left(\frac{1}{6} \times 3\right) + \left(\frac{1}{6} \times 8\right) + \left(\frac{1}{6} \times 5\right) + \left(\frac{1}{6} \times 12\right) \][/tex]

[tex]\[ \text{Expected Value} = \frac{1}{6}(1 + 4 + 3 + 8 + 5 + 12) \][/tex]

[tex]\[ \text{Expected Value} = \frac{1}{6}(33) \][/tex]

[tex]\[ \text{Expected Value} = 5.5 \][/tex]

Therefore, the expected value per roll that Chris will get is [tex]$5.50. Thus, the correct answer is: C. $[/tex]5.50