Ineed with this equation i got for homework

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?

Hurry the figure shows the front side of a metal desk in the shape of a trapezoid.what is the area of this trapezoid? 10 ft²16 ft²32 ft²61 ft²

Find the combined area of the triangles. click on the answer until the correct answer is showing.possible answers: a = 4 pi - 8a = 9 pi - 9/2 √3a = 16/3 pia = 16a = 27 pi