Mr. Sharma travels by car and covers 25% of his journey with a speed of 10 km/h, 45% of his journey with a speed of 5km/h and remaining 30% of his journey with a speed of 15km/ h. What will be the average speed of Mr. Sharma for the whole journey?

Answer

To find the average speed of Mr. Sharma for his entire journey, we will follow these steps:

### Step 1: Define the total distance
Assume the total distance of the journey is 100 km. This makes calculations easier since we can directly use percentages.

### Step 2: Calculate the distance covered at each speed
- **Distance covered at 10 km/h:**
25% of 100 km = 25 km
- **Distance covered at 5 km/h:**
45% of 100 km = 45 km
- **Distance covered at 15 km/h:**
30% of 100 km = 30 km

### Step 3: Calculate the time taken for each segment of the journey
- **Time taken for the first segment (25 km at 10 km/h):**
Time = Distance / Speed = 25 km / 10 km/h = 2.5 hours
- **Time taken for the second segment (45 km at 5 km/h):**
Time = Distance / Speed = 45 km / 5 km/h = 9 hours
- **Time taken for the third segment (30 km at 15 km/h):**
Time = Distance / Speed = 30 km / 15 km/h = 2 hours

### Step 4: Calculate the total time taken for the journey
Total time = Time for first segment + Time for second segment + Time for third segment
Total time = 2.5 hours + 9 hours + 2 hours = 13.5 hours

### Step 5: Calculate the average speed
Average speed = Total distance / Total time
Average speed = 100 km / 13.5 hours ≈ 7.41 km/h

### Final Answer
The average speed of Mr. Sharma for the whole journey is approximately **7.41 km/h**.

---