Help ASAP:D I I rlly don't get it

The volume of a cube is 8 in to the 3rd power. how long is each side?

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?

Tatiana reads 40 pages of her book every night for x number of nights. write an expression that shows the number of pages she has read