; Intermediate Student or higher.  Doesn't require any teachpacks.

; can-vote? : number => boolean
(define (can-vote? age)
  (>= age 18))
"Examples of can-vote?:"
(can-vote? 17) "should be false"
(can-vote? 18) "should be true"
(can-vote? 97) "should be true"

; voting-message : string => string
(define (voting-message text)
  (local [(define age (string->number text))]
    (cond [(not (number? age))
           (format "I don't understand ~s; the age must be a number." text)]
          [(>= age 18) (format "~s is old enough to vote.  Congratulations!" age)]
          [(< age 18) (format "~s is NOT old enough to vote yet." age)])))
"Examples of voting-message:"
(voting-message "18") "should be \"18 is old enough to vote.  Congratulations!\""
(voting-message "17") "should be \"17 is NOT old enough to vote.\""
(voting-message "p3n890") "should be \"I don't understand \"p3n890\"; the age must be a number.\""