PLEASE HELP I NEED AN ANSWER ASAP An online history quiz had 500 total people take it. Of the 500 people, 7% got all of the questions correct and 11% answered all of the questions wrong. How many more people answered all the questions wrong than answered all the questions correctly?

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?