Aladder that is 32 ft long leans against a building. the angle of elevation of the ladder is 70 degrees

how high off the ground is the top of the

a.20ft
b.30ft
c.26ft
d.39ft

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?