You are responsible for detecting the source of errors when the computer system fails. From your analysis you know that the source of error is the disk drive, computer memory, or the operating system. You know that 50% of the errors are disk drive errors, 30% are computer memory errors, and the remainders are operating errors. From the component performance standards you know that, when a disk drive error occurs, the probability of failure is 0.7; when a computer memory error occurs, the probability of failure is 0.6; and when an operating system error occurs, the probability of failure is 0.3. Using the information from the component performance standards, what is the probability of a disk drive error given that a failure occurred?