Answer: It means the tours leave at the same time after every 1 hour.
Explanation:
Since we have given that
Number of every minutes that tours for the national capital leave = 15 minutes
Number of every minutes that tours for the White house leave = 20 minutes
We need to find the number of minutes, the tours leave at the same time.
So, to leave for the same time = L.C.M. of 15 and 20 = 60 minutes
Hence, It means the tours leave at the same time after every 1 hour.