1) There are 80 homes in a subdivision. A realtor tells you that 50 of the homes have vinyl siding, 20 of the homes have automatic sprinkler systems, and 15 of the homes have both.

a) How many of the homes have vinyl siding, but no automatic sprinkler system?

b) How many of the homes have neither vinyl siding nor an automatic sprinkler system?

2) An opinion poll was conducted. Respondents were classified according to their age (over 40 or under 40), political affiliation (Democrat, Independent, Republican), and the region of the country in which the reside (Northwest, West, Central, South, East, North East). How many ways are there to classify a person who is under 40 ?

Please show me the formula or a step by step on how you retrieved these answers. Thank you.