Alex is adding baseball cards to sleeves and his binder he filled 2/7 of His Banner the first day on the second day he feels for 7 how much of his binder did Alex bill in those two days

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?