Gavin is working two summer jobs, making $20 per hour lifeguarding and making $6 per hour walking dogs. In a given week, he can work no more than 10 total hours and
must earn at least $90. If z represents the number of hours lifeguarding and y
represents the number of hours walking dogs, write and solve a system of inequalities
graphically and determine one possible solution.

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?