Three men start together on a circular track which is 1 km in circumference from same point at same time in same direction. If their speeds are 10 m/min, 20 m/min and 40 m/min. Then find after how much time they will be together at same place?

25 minutes

Distance = 1000meters

LCM of their speeds (10, 20, 40) = 40

Time they will be together at same place = \(\frac{Distance}{LCM \; of \;their \;speeds}\)

Time they will be together at same place = \(\frac{1000}{40}\)

                                                                 = 25 minutes