the same ice cream shop is running a sale on cylindrical shaped tubs of ice cream. The cylinder has a radius of 4.5 cm and a height of 18 cm. Find the volume of a tub of ice cream​

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?