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?
Answer:
Probability = 0.084
Step-by-step 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