A parents' evening was planned to start at 16:30. There were 20 consecutive appointments of 10 minutes each and
a break of 15 minutes during the evening.
At what time was the parents' evening due to finish?
Give your answer using the 24-hour clock
hours
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Assume that there is a 11% rate of disk drive failure in a year. a. if all your computer data is stored on a hard disk drive with a copy stored on a second hard disk drive, what is the probability that during a year, you can avoid catastrophe with at least one working drive? b. if copies of all your computer data are stored on four independent hard disk drives, what is the probability that during a year, you can avoid catastrophe with at least one working drive?