Final answer:
The final average velocity is found by taking the total distance traveled (720 km) and dividing it by the total time taken (3.883 hours), resulting in an average velocity of approximately 185 km/hr, which rounds to 185 km/hr (Option D).
Step-by-step explanation:
To calculate the final average velocity, we need to find the total distance traveled and divide it by the total time taken, including the time stopped. Firstly, the student drove for 20 km at 150 km/hr, which would take them 20 km / 150 km/hr = 0.133 hours (or 8 minutes). After a quarter-hour break (0.25 hours) to replace the tire, they then drove for another 3.5 hours at 200 km/hr. The distance covered during the last part of the trip is 200 km/hr × 3.5 hr = 700 km.
To calculate the total distance traveled: 20 km + 700 km = 720 km. The total time taken includes the driving time and the break time: 0.133 hours + 3.5 hours + 0.25 hours = 3.883 hours. Now, the final average velocity is the total distance divided by the total time which gives us 720 km / 3.883 hr = 185.46 km/hr. Therefore, rounding to the nearest whole number, the final average velocity is 185 km/hr (Option D).