High School

A survey of 200 people yielded the following information: 96 people owned a Blu-ray player, 123 owned a microwave oven, and 78 owned both. How many people owned the following?

(a) A Blu-ray player or a microwave oven

(b) A Blu-ray player but not a microwave oven

(c) A microwave oven but not a Blu-ray player

(d) Neither a Blu-ray player nor a microwave oven

Answer :

(a) 141 people, (b) 18 people, (c) 45 people, (d) 59 people owned neither a Blu-ray player nor a microwave oven.

To solve this problem, let's use the principle of inclusion-exclusion:

(a) To find the number of people who owned either a Blu-ray player or a microwave oven, we add the number of people who owned a Blu-ray player to the number of people who owned a microwave oven and then subtract the number of people who owned both to avoid double-counting.

[tex]\[ \text{(a)} = \text{Blu-ray player} + \text{Microwave oven} - \text{Both} \][/tex]

[tex]\[ \text{(a)} = 96 + 123 - 78 = 141 \][/tex]

(b) To find the number of people who owned a Blu-ray player but not a microwave oven, we subtract the number of people who owned both from the total number of Blu-ray player owners.

[tex]\[ \text{(b)} = \text{Blu-ray player} - \text{Both} \][/tex]

[tex]\[ \text{(b)} = 96 - 78 = 18 \][/tex]

(c) To find the number of people who owned a microwave oven but not a Blu-ray player, we subtract the number of people who owned both from the total number of microwave oven owners.

[tex]\[ \text{(c)} = \text{Microwave oven} - \text{Both} \][/tex]

[tex]\[ \text{(c)} = 123 - 78 = 45 \][/tex]

(d) To find the number of people who owned neither a Blu-ray player nor a microwave oven, we subtract the total number of people who owned either or both devices from the total number of people surveyed.

[tex]\[ \text{(d)} = \text{Total} - \text{(a)} \][/tex]

[tex]\[ \text{(d)} = 200 - 141 = 59 \][/tex]

So, the answers are:

(a) 141 people

(b) 18 people

(c) 45 people

(d) 59 people

Using the inclusion-exclusion principle, the number of people who owned a Blu-ray player or a microwave oven is 141, 18 owned only a Blu-ray player, 45 owned only a microwave oven, and 59 owned neither.

The question involves applying principles of set theory to a real-world problem related to ownership of Blu-ray players and microwave ovens. To solve this, we utilize the inclusion-exclusion principle. Let's denote the number of people who own a Blu-ray player as B and the number of people who own a microwave oven as M. According to the question:

B (Blu-ray owners) = 96

M (Microwave owners) = 123

B \\cap M (Both Blu-ray and microwave owners) = 78

To answer the following:

(a) a Blu-ray player or a microwave oven: We use the formula Total = B + M - B \\cap M.

Thus, Total = 96 + 123 - 78 = 141 people.

(b) a Blu-ray player but not a microwave oven: This is calculated as B - B \\cap M.

Thus, we have 96 - 78 = 18 people.

(c) a microwave oven but not a Blu-ray player: This is M - B \\cap M.

Hence, 123 - 78 = 45 people.

(d) neither a Blu-ray player nor a microwave oven: This is the total number surveyed minus those that own either one, so 200 - 141 = 59 people.