To find the average speed, we can use the formula:
Average Speed = Total Distance / Total Time
Let's assume the total distance covered by the car is "D" kilometers.
The car covers 2/5 * D distance at a speed of 80 km/hr, which means it covers (2/5)D kilometers in 80 km/hr. Using the formula Speed = Distance / Time, we can calculate the time taken to cover this distance:
Time1 = Distance1 / Speed1 = (2/5)D / 80 = (2D/5) / 80 = 2D / (5 * 80) = D / 200
Similarly, the car covers 3/5 * D distance at a speed of 60 km/hr, which means it covers (3/5)D kilometers in 60 km/hr. Using the formula Speed = Distance / Time, we can calculate the time taken to cover this distance:
Time2 = Distance2 / Speed2 = (3/5)D / 60 = (3D/5) / 60 = D / (5 * 60) = D / 300
Now, let's find the total distance covered by the car:
Total Distance = (2/5)D + (3/5)D = (2D + 3D) / 5 = 5D / 5 = D
The total time taken by the car is the sum of Time1 and Time2:
Total Time = Time1 + Time2 = D / 200 + D / 300 = (3D + 2D) / (3 * 200) = 5D / 600 = D / 120
Now, we can calculate the average speed:
Average Speed = Total Distance / Total Time = D / (D / 120) = 120
Therefore, the average speed of the car is 120 km/hr.