express the distance d between the cars as a function of time t

Question

express the distance d between the cars as a function of time t

Answer 1

Car A goes 50 mph, Car B goes 40 mph

they start from the same point and drive in the same direction

the distance between them is d(t) = 10t

after two hours they'll be 10(2) = 20 miles apart

distance = speed times time

more generally

d(t) = (A-B)t where A and B are the cars' speeds in mph and t is measured in hours, d in miles