You have a $20 phone card. calls made using the card cost $.03 per minute to destinations in the united states and $.06 per minute to destinations in brazil. write an inequality describing the numbers of minutes you can use for calls to the u. s. and brazil.

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?