You’re working on saving up your hard-earned money. You currently have $150 saved up and you got a job babysitting and now make $12 per hour. Your goal is have at least $500 saved up for your next big purchase. Please solve using a inequality

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?