The fisherman with the longest fish wins a fishing competition. about how much longer is the first place fish than the third place fish?

the first place fish is 68.7 and the third place fish is 58.2

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?