sapeed and distance comparison

[fbray123]

is there a formula to calculate how long it would take one moving object (car etc) to catch another moving object if they were travelling at different speeds?

[Trevilino]

If my logic is right t = a/(y-b)

Where t = time to catch the other car (hours)
a = the distance the other car is in front (miles or Kilometres)
y=the speed pf the car behind (mph or kph)
b= the speed of the car in front (mph or kph)

e.g. if car 1 travelling at 10mph is 15 miles ahead of car 2 travelling at 15 mph the it will take 15/(15-10) = 3 hours.
To check:- car 1 has travelled 15 miles + 3*10=45 miles.
Car 2 has travelled 3*15 = 45 miles. QED