According to data from the U.S. State Department, the percentage of Americans who have a passport has risen dramatically. In 2007, only 27% of Americans had a passport; in 2017 that percentage had risen to 42%. Assume that currently 42% of Americans have a passport. Suppose 50 Americans are selected at random.

a. Find the probability that fewer than 20 have a passport.

b. Find the probability that at most 24 have a passport.

c. Find the probability that at least 25 have a passport.