Investors buy a studio apartment for $200,000. Of this​ amount, they have a down payment of $20,000. Their down payment is what percent of the purchase​ price? What percent of the purchase price would an ​$80,000 down payment​ be?

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?