Perry surveyed 60 students at her school and found that 0.45 of the students she surveyed said their favorite class is math. another 35% of the students she surveyed reported that their favorite class is science. how many more students in the survey prefer math over science? 6 7 27 21

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?