3.119 You are responsible for detecting the source of the error when a computer system fails. From your analysis you know that the source of error is the disk drive, the computer memory, or the operating system. You know that 50% of the errors are disk drive errors, 30%

are computer memory errors, and the remainder are operating system errors. From the component performance standards, you know that when a disk drive error occurs, the probability of failure is 0.60; when a computer memory error occurs, the probability of failure is 0.7; and when an operating system error occurs, the probability of failure is 0.3. Given the information from the component performance standards, what is the probability of a disk drive error, given that a failure occurred?