According to a February 2005 survey completed by the Pew Internet & American Life Project, about 36 million Americans, or 27% of Internet users, say they download either music or video files. Assuming the percentage is correct, use the normal approximation to the binomial to find the probability of the following in a survey of 2000 American Internet users.

Source: http://www.pewinternet.org/PPF/r/153/report_ display.asp

a. At least 500 download music or video files

b. At least 575 download music or video files

c. At most 520 download music or video files

d. At most 555 download music or video files