Can you also pls help me with this one?

Find the third,fifth and seventh term sequence described by each rule a(n)=n+1

Arace is 10 kilometers long.markers will be placed at the beginning and end of the race course and at each 500 meter mark.how many markers are needed to mark the course for the race?

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)?