Find the volume of a cone with a height of 8yd and a base diameter of 6yd use the value 3.14 for pi and do not do any rounding. be sure to include the correct unit in your answer

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?