SSC MTS 6 Aug 2019 Shift 2 Paper

Average speed = 2xy/(x + y)
Here, x = speed from A to B
y = speed from B to A
⇒ Average = 2 × 30 × 20/(30 + 20)
⇒ Average = 24 km/h
∴ The average speed for the entire journey is 24 km/h.