Enrique lives with his grandmother in an apartment building for senior citizens. he earns extra money by running errands for some of his grandmother's neighbors. enrique charges $2 for every
1
7
hour he spends working. he spent
5
7
hour going to the deli for mr. mcguire, 1
1
7
hours delivering papers for the apartment manager, and
6
7
hour picking up mrs. shultz's groceries.
did enrique earn enough money to buy a $34 dvd?

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?