22. A gym subscription runs several promotions. Customers can choose from the following deals:
Option A: 25% off an annual subscription of $308.00
Option B: pay $29 per month
How much will a customer save by purchasing the annual subscription over paying per month?

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?