The Centers for Disease Control and Prevention reports that 25% of baby boys 6–8 months old in the United States weigh more than 20 pounds. A sample of 150 babies is studied.

a. Approximate the probability that more than 40 weigh more than 20 pounds.

b. Approximate the probability that 35 or fewer weigh more than 20 pounds.

c. Approximate the probability that the number who weigh more than 20 pounds is between 30 and 40, exclusive.