Question

In a home theater system, the probability that the video components need repair within 1 year is 0.02, the probability that the electronic components need repair within 1 year is 0.007, and the probability that the audio components need repair within 1 year is 0.001. Assuming that the events are independent, find the following probabilities. (Round your answers to four decimal places.)

(a) At least one of these components will need repair within 1 year
(b) Exactly one of these component will need repair within 1 year

Answer 1

(a) The probability that at least one of these components will need repair within 1 year is 0.0278.

(b) The probability that exactly one of these component will need repair within 1 year is 0.0277.

Explanation:

Denote the events as follows:

A = video components need repair within 1 year

B = electronic components need repair within 1 year

C = audio components need repair within 1 year

The information provided is:

P (A) = 0.02

P (B) = 0.007

P (C) = 0.001

The events A, B and C are independent.

(a)

Compute the probability that at least one of these components will need repair within 1 year as follows:

P (At least 1 component needs repair)

= 1 - P (No component needs repair)

`=1-P(A^(c)\cap B^(c)\cap C^(c))\\=1-[P(A^(c))* P(B^(c))* P(C^(c))]\\=1-[(1-0.02)* (1-0.007)* (1-0.001)]\\=1-0.97216686\\=0.02783314\\\approx 0.0278`

Thus, the probability that at least one of these components will need repair within 1 year is 0.0278.

(b)

Compute the probability that exactly one of these component will need repair within 1 year as follows:

P (Exactly 1 component needs repair)

= P (A or B or C)

`=P(A\cap B^(c)\cap C^(c))+P(A^(c)\cap B\cap C^(c))+P(A^(c)\cap B^(c)\cap C)\\=[0.02* (1-0.007)* (1-0.001)]+[(1-0.02)* 0.007* (1-0.001)]\\+[(1-0.02)* (1-0.007)* 0.001]\\=0.02766642\\\approx 0.0277`

Thus, the probability that exactly one of these component will need repair within 1 year is 0.0277.