I am very confident in my excel formulas for calculating b and c, but I am not so confident about a and d. Take note of "and" and "or". What are the steps for finding probability of more than one event?

Find probability that respondent is:

a. Freshman or eat daily at campus dining facility

b. Sophomore and eat weekly at campus dining facility

c. Junior and does not eat daily at campus dining facility

d. Senior or does not eat monthly at campus dining facility

Here is the data:

Year in School	Frequency		For year in school
1	5		1 = Freshman
1	4		2 = Sophomore
2	1		3 = Junior
1	1		4 = Senior
1	1
4	4		For Frequency
1	1		1 = Daily
1	4		2 = 2 or 3 times per week
1	5		3 = Weekly
1	3		4 = 2 or 3 times per month
3	5		5 = Once a month or less
1	3
3	5
1	1
4	5
2	1
4	4
3	5
1	3
4	1
3	1
2	1
2	1
2	5
3	2
2	5
2	2
2	1
2	1
4	3
4	5
4	3
4	2
4	3
3	1
3	1
2	1
2	2
3	1
4	3
2	1
2	5
4	1
3	1
4	1
4	2
3	2
2	3
3	5
4	1
1	2
4	2
2	2
1	5
1	1
1	5
2	5
3	3
2	2
4	1
2	1
3	1