Given: Bus’s speed from Town R to Town S = 29 kmph Bus’s speed from Town S to Town R = 26 kmph Formula Used: Average Speed = 2 (A × B) / (A + B) Calculations: As two equal distance are covered at two different speed Average Speed = 2 (A × B) / (A + B) ⇒ Average Speed = 2 × 29 × 26 / (29 + 26) ⇒ Average Speed = 1508 / 55 ⇒ Average Speed = 27.41 ≈ 27. The approximate average speed of the bus is 27 kmph.