In a study by Peter D. Hart Research Associates for the Nasdaq Stock Market, it was determined that 20% of all stock investors are retired people. In addition, 40% of all adults invest in mutual funds. Suppose a random sample of 25 stock investors is taken.

a) Suppose a random sample of 20 adults is taken. What is the probability that exactly seven adults invested in mutual funds?

P(x = 7)=

b) Suppose a random sample of 20 adults is taken. What is the probability that fewer than five adults invested in mutual funds?

P(x < 5)=

c)Suppose a random sample of 20 adults is taken. What is the probability that exactly two adults invested in mutual funds?

P(x = 2)=

d)Suppose a random sample of 20 adults is taken. What is the probability that 11 or more adults invested in mutual funds?

P(x ≥ 11)=