What is 0.18 repeating as a fraction

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?

At your job you're paid $50 per week plus $3 per sale at least how many saled do you need to make in order to have over $250

Atriangle has side lengths of x, x+11, and 3x+5. what is the perimeter?