Final answer:
By calculating the distance covered at each speed and summing those, we determine that the vehicle travels 35 km after 30 minutes, with 20 km in the first 20 minutes at 60 km/h and 15 km in the last 10 minutes at 90 km/h.
Step-by-step explanation:
To determine the total distance covered by the vehicle, we can calculate the distance traveled at each speed and then sum those distances.
For the first part of the journey, the vehicle travels at 60 km/h for 20 minutes. To find the distance, we convert 20 minutes to hours (20 minutes = 1/3 hour) and then use the formula distance = speed × time. So, the distance for the first part is 60 km/h × 1/3 h = 20 km.
For the second part, the vehicle travels at 90 km/h for 10 minutes. Converting 10 minutes to hours gives us 10 minutes = 1/6 hour. Therefore, the distance for the second part is 90 km/h × 1/6 h = 15 km.
Adding both distances together gives us the total distance: 20 km + 15 km = 35 km.
At the end of 30 minutes, the vehicle has covered a distance of 35 km.