Question: A directory on a computer's hard disk contains 12 files, 3 of which have viruses. If a file with a virus is selected, the virus is detected and another file is then selected. Find the expected number of files that must be selected in order to get a virus-free file.
2. At a gambling casino, a ball will be drawn from a bin containing 43 red balls, 27 green balls, and 8 blue balls. A player marks a game card with the color he or she believes will be picked. The prize money for guessing the correct color is
Red $3.00
Green $6.00
Blue $10.00
The price of the game card is $5.00. Find the expected value of the prize money.