A cell phone battery charges at a rate of 16% every thirty minutes. When initially plugged into the charger, a cell phone has 10% battery.

1. Write an equation relating the amount of time, measured in hours, it takes to charge a cell phone as a function of the battery charge.
2. Use complete sentences to describe the rate in which the battery charges in terms of the time that it is charging.

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?