Jackie has fewer than 20 h to work on her jewelry. It takes her half an hour to make a necklace and an hour to make a bracelet. She wants to make x necklaces and y bracelets, and she wants at least twice as many bracelets as necklaces. Select all inequalities that model this situation.

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?