A man travelled by car from city A to city B at a speed of 24 km/h and returned from city B to city A at 16 km/h. Find his average speed over the whole journey.

19.5 km/h 20 km/h 19 km/h 19.2 km/h

19.2 km/h

Average Speed = \(\frac{ 2 × S1 × S2}{S1 + S2}\) S1 = 24 km/h & S2 = 16 km/h  is given Average Speed = \(\frac{ 2 × 16 × 24}{16 + 24}\) = \(\frac{ 768}{40}\) = 19.2 km/h Average speed = 19.2 km/h