How do you do these problems? For Math 218 (Note: I have right answers, I just need to know how to do these for my exam, thank you)

1.In September(30 days), the temperature in a particular city reached 100 degrees F on 20 days.Also, measureable rain fell at thecity's airport on 10 days, and on 2 days, both events occurred.

a) On how many days did at least one of the eventsoccur?

b) On how many days did the temperature reach 100degrees

c) On how many days did the temperature not reach 100degrees

2.In a certainstate, it has been shown that only 50 percent of the high school graduates who are capable of college work actually enroll in college. Find the probabilitythat, among 10 capable high school graduates in thisstate, 5 to 7inclusive will enroll in college.

The probabilitythat, among 10 capable high school graduates in thisstate, from 5 through 7 will enroll in college is...

3.A survey indicated that 10 percent of residents of a country have a great deal of confidence in banks and financial institutions. If 18 residents of the country were chosen atrandom, find the probability that at most 2 residents had a great deal of confidence in banks and financial institutions.

The probability that at most 2 residents had a great deal of confidence in banks and financial institutions is.....

4.A survey indicated that 14 percent of residents of a country have a great deal of confidence in banks and financial institutions. If 13 residents of the country were chosen atrandom, find the probability that none residents had a great deal of confidence in banks and financial institutions.

The probability that none residents had a great deal of confidence in banks and financial institutions is

5.A six-digit number starts with a number between 6-9 in the firstposition, with no restrictions on the remaining 5 digits.

a) The probability that arandomly-chosen number contains all different digits is....

b) The probability that arandomly-chosen number contains at least one repeated digit is....

6.AtTechnodynamics, Inc., arandomly-selected hiring committee of 4 people is formed from a group of 4 employees in marketing and 6 employees in management.

a) Find the probability that the committee has exactly 3 employees from marketing.

b) Find the probability that the committee has at least one employee from marketing.

c) Find the probability that the committee has at most one employee from management.