How do you write 68% as a fraction in simplest form?

Which statements are true? see picture

Given the equation f(x)=a(b)x where the initial value is 40 and the growth rate is 20% what is f(4)

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?