(define seconds-in-a-day (* 24 60 60))
(define seconds-in-an-hour (* 60 60))

(define (how-many-days-hours-minutes-seconds n)
  (let ((days     (quotient n seconds-in-a-day))
        (n-rest-1 (modulo n seconds-in-a-day))
        (hours    (quotient  n-rest-1  seconds-in-an-hour))
        (n-rest-2 (modulo  n-rest-1  seconds-in-an-hour))
        (minutes  (quotient  n-rest-2  60))
        (seconds  (modulo  n-rest-2  60))
       ) 
    (list days hours minutes seconds)))