At a speedway, the yellow car completes a lap every 30 seconds and the blue car completes a a lap every 50 seconds. If the cars both start at the same place, how long will it take for the blue car to 'lap' the yellow car?

Answer 1

lapping means the yellow car passes the blue car
... it has completed one more lap than the blue car

t = time to lap ... in seconds

t / 30 = (t / 50) + 1