;; How to design a program (define (profit ticket-price) (- (revenue ticket-price) (cost ticket-price)))(define (revenue ticket-price) (* (attendees ticket-price) ticket-price))(define (cost ticket-price) (+ 180 (* .04 (attendees ticket-price))))(define (attendees ticket-price) (+ 120 (* (/ 15 .10) (- 5.00 ticket-price))))
(define (area-of-disk r) (* 3.14 (* r r)))
(define (area-of-ring outer inner) (- (area-of-disk outer) (area-of-disk inner)))