while i tend to agree with "Hooo" and consider it a simple/'trick' question,
there is another way to look at it (normal procedure in many races):
car a might have passed a point where a stop watch was triggered
car b passes this point 15 seconds later
at this point in time car a has traveled 15*29.3 feet further, so the distance between the cars is 439.5 feet at this time
then it would take ~29.9 seconds for the second car to catch up
(all this assuming that it's 29.3 feet and not 29 feet 3 inches)
definitely poor wording of the question
take your pick