A store is instructed by corporate headquarters to put a markup of 25​% on all items. An item costing ​$16 is displayed by the store manager at a selling price of ​$4. As an​ employee, you notice that this selling price is incorrect. Find the correct selling price. What was the​ manager's likely​ error?

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?