Tribeni had to travel 175 km in 3.5 hours. However, she travelled at the rate of 58 km/hr for 2.5 hours and then rested for 20 minutes before completing the journey. If Tribeni managed to reach on time, her speed during the last stretch would have been

Options

A. 36 km/hr
B. 30 .km/hr
C. 42.5 km/hr
D. 45 .km/hr

Answer

To find Tribeni's speed during the last stretch of her journey, we will follow these steps:

### Step 1: Calculate the total distance and time.
Tribeni had to travel a total distance of 175 km in 3.5 hours.

### Step 2: Calculate the distance covered in the first part of the journey.
Tribeni traveled at a speed of 58 km/hr for 2.5 hours.
- Distance covered = Speed × Time = 58 km/hr × 2.5 hr = 145 km.

### Step 3: Calculate the remaining distance.
- Remaining distance = Total distance - Distance covered = 175 km - 145 km = 30 km.

### Step 4: Calculate the total time spent so far.
- Time spent traveling = 2.5 hours.
- Time spent resting = 20 minutes = 20/60 hours = 1/3 hours.
- Total time spent = 2.5 hours + 1/3 hours = 2.5 + 0.333 = 2.833 hours (approximately).

### Step 5: Calculate the remaining time to complete the journey.
- Total time allowed = 3.5 hours.
- Remaining time = Total time - Time spent = 3.5 hours - 2.833 hours = 0.667 hours (approximately).

### Step 6: Convert remaining time to minutes.
- Remaining time in minutes = 0.667 hours × 60 minutes/hour = 40 minutes.

### Step 7: Calculate the speed required to cover the remaining distance.
Using the formula: Speed = Distance / Time,
- Speed = Remaining distance / Remaining time = 30 km / (40/60 hours) = 30 km / (2/3 hours) = 30 km × (3/2) = 45 km/hr.

### Final Answer:
Tribeni's speed during the last stretch would have been **45 km/hr**.

---