Two model trains begin at the toy train station and travel continuously on two circular tracks of equal length. The first train completes a circuit in 20 seconds and the second train in 15 seconds. If both trains leave the station at the same time, after how many seconds will the two trains first meet again?
The answer is 60 seconds but I don't know how they got this. Please help?
To find out when the two trains will first meet again, you need to find the least common multiple (LCM) of their individual circuit times.
The first train completes a circuit in 20 seconds, so it will complete 3 circuits in 60 seconds (20 x 3 = 60).
The second train completes a circuit in 15 seconds, so it will complete 4 circuits in 60 seconds (15 x 4 = 60).
Since both trains complete a whole number of circuits in the same amount of time (60 seconds), they will meet again after 60 seconds.