What is the sum of the first five terms of the geometric sequence in which a1=5 and r= 1/5? Express your answer as an improper fraction using the slash (/) key and no spaces.

Charlie is at an amusement park that has 18 different rides. each ride costs $1.75. the function c(r) = 1.75r represents the total amount of money that charlie will spend if he goes on r rides, but he never goes on the same one more than once. what domain and range are reasonable for the function?