an endangered species is the subject of a protection program. the formula below models the species population, p, after x years of the protection program, where 0≤ x ≤12. after how long is the population up to 3550? use the formula below.

p=−10x2+245x+3100

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?