31,32,32,33,34,35,35,35,35 what number is the median

Which recursive formula can be used to determine the total amount of money earned in any year based on the amount earned in the previous year? f(n+1)=f(n)+5

How do i do this activity, is appreciated

An appliance store sells lamps at $95.00 for two. a department store sells similar lamps at 5 for $250.00. which store sells at a better rate