1.There are 50 reports to be read. Ten are to be chosen for today's work. How many different possibilities are there for choosing the reports? If 5 of the 50 reports are important, what is the probability that at least 1 important report is read?

2.Every page in a certain book has a probability of 1 in 50 of having an error on it. If forty pages are examined, what is the probability of there being exactly two pages with errors on them?

3.A certain population has an income distribution given by a normal random variable whose mean is $35000 and whose standard deviation is $7500. What is the probability that a randomly selected person has an income less than $19000?