Identify whether each scenario would be represented by a continuous or discrete graph

Which of the fallowing best completes the sequence 12,8,5, a) 1 b) 2 c)4 d)0

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?

Find the center of the circle that can be circumscribed about efg with e(4,4) f(4,2) g(8,2)