For 1st Km
Given - speed = 60 km/hr and distance = 1 km
Time = distance/speed = 1/60 Km/hr
For next 1 Km
Given - speed = 40 km/hr and distance = 1 km
Time = distance/speed = 1/40 Km/hr
Average Speed = Total Distance / Total Time
= (1 + 1) / (1/60 + 1/40)
= 2 * 2400/100
= 48 Km/hr
Answer - The average speed of the car is 48 Km/hr