Final answer:
Brad perceives Lee as moving faster because their speeds add up when they're cycling in opposite directions. This combined relative speed is 57 mph, which is much faster than Lee's actual speed of 33 mph.
Step-by-step explanation:
When both Brad and Lee are cycling in opposite directions, the speed at which they appear to be moving away from each other is the sum of their individual speeds. Since Brad is cycling at 24 mph and Lee is cycling at 33 mph, to Brad it would appear that Lee is moving away at a speed of 24 mph + 33 mph = 57 mph, much faster than Lee's actual speed. This is because when two objects are moving in opposite directions, their speeds relative to each other are additive. Therefore, it seems to Brad that Lee is travelling faster than his actual speed of 33 mph.