3/4 times 16 what is it

Find cot x if sin x cot x csc x = √2

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?

Ineed the solution to this problem and the steps.