Given that a computer required service, what is the probability that it was a laptop? Given that the computer required service, the probability that it was a laptop is nothing?

Complete Question:

A campus bookstore sells both types and in the last semester sold 56% laptops and 44% desktops. Reliability rates for the two types of machines are quite different, however. In the first year, 5% of desktops require service, while 15% of laptops have problems requiring service.

Given that a computer required service, what is the probability that it was a laptop?

Probability = 0.084

Explanation:

Given

Laptops = 56%

Desktop = 44%

Service Required (Laptop) = 15%

Service Required (Desktop) = 5%

Required

Determine the probability that a selected computer is a laptop and it requires service.

The question tests our knowledge of probabilities using "and" condition.

What the question requires is that, we calculate the probability of selecting a LAPTOP that REQUIRES SERVICE

Note the capitalised words.

This will be calculated as follows:

Probability = P(Laptop) and P(Service Required (Laptop))

[Substitute values for P(Laptop) and P(Service Required (Laptop))]

Probability = 56% * 15%

[Convert to decimal]

Probability = 0.56 * 0.15

Probability = 0.084