Runner A can circle a track in 60 seconds, and runner B can circle a track in 65 seconds. If they start at the same time, after how many seconds does runner A pass runner B?
Runner A runs faster than B ..... every lap A gets closer to B
Each lap takes A 5 seconds less than B 60 seconds/ 5 seconds/lap = 12 laps
in 12 laps B has taken 12 x 65 = 780 seconds in 780 seconds A will have run 780 / 60 = 13 laps and will be at the same spot as B