Abus took a seven hour trip and traveled 330 miles. the speed was 54 mph for the first part of the trip, and then decreased to 30 mph for the second part of the trip. how many hours were traveled at each speed? 54 and 30

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?