Determine if the sequence below is arithmetic or geometric and determine the common difference / ratio in simplest form. 9,3,1

This is sequece and the is equal to

first blank - arithmetic or geometric
2nd blank- common difference or common ratio

How do you find p(a and b) if a and b are independent events for two or more actions, such as tossing a coin twice and finding p(heads and heads)? 2. how do you find p(a or b) if a and b are independent events for one action, such as spinning a four-color spinner once and finding p(red or blue)?