A dolphin went 15 feet below sea level to catch a fish. A shark went twice as deep, then swam down an additional 10 feet to catch a larger fish. Which expression represents the shark’s position in relation to sea level? 2 A. 2 (-15) + (-10) B. 2(-15)+10 C. 2 (-15) - (-10) D. 2 (-15)- (-10)

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?