The light from a lightning bolt reaches your eyes almost instantaneously (travelling at the speed of light), but the thunder travels at the much slower rate of 5 miles a second. Thus you can estimate your distance from a lighting strike by counting the seconds between seeing the lighting and hearing the thunder, then dividing by five.
However, your high-school friend, Dwayne (who is now in the honors program at Boston University), has trouble with the math involved in this concept. So you decide to help him out by automating the task.
Design a Scheme function for Dwayne that converts the elapsed time in seconds between lighting and thunder into the distance in miles between you and the strike.
;;; Grader: Christos ;;; Note: problem statement is wrong -- the correct calculation is ;;; to *multiply* by five, not divide. Give full credit for either ;;; the bogus, requested solution (divide), or the correct solution ;;; (multiply). ;;; lightning-distance: Number -> Number [1pt] ;;; Distance from lighting given thunder arrival time. [1pt] ;;; Example: given 20, the distance is 4. [1pt] (define (lightning-distance time-diff) ;; [2pt for requested definition] (/ time-diff 5)) ;;; Tests: [1pt, 2 if there is no example] (equal? (lightning-distance 20) 4) (equal? (lightning-distance 15) 3)