A bus travelled a total distance s. it covered its journey in consecutive one-third distances with speeds 60km/hr, 70km/hr and 80km/hr, respectively. Calculate the average speed of bus for entire journey.

Explanation

To find the average speed of the bus over its entire journey, we can follow these steps:

### Step 1: Define the total distance and segments
Let the total distance traveled by the bus be \( S \). The bus covers this distance in three equal segments, each of length \( \frac{S}{3} \).

### Step 2: Identify the speeds for each segment
The speeds for each segment are:
- From A to C (first segment): \( v_1 = 60 \) km/hr
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