Edwin is working on his oral report about polyhedrons for his math class. He will show figures and organize them in different groups during his report. Edwin says that he
can show a figure with a square base and congruent triangular faces. Is Edwin correct? Explain your reasoning.

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?