Five stars notebooks cost $4.00 more than cvs notebooks. if marina were to buy 8 five stars notebooks then she will have to spend $16.00 more than if she were to buy 10 cvs notebooks. how much does each notebook cost? need asap

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?