Tony is reseeding the front lawn. The lawn covers 2,500 square feet and grass seed is $15.98 for each 7-pound bag. Each pound of grass seed covers 150 square feet. How many bags are needed to seed the 2500 square feet lawn?

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?