Final answer:
The truck's average velocity is 0.5 km/min, which is calculated by dividing the displacement of 15 km by the time taken of 0.5 hours and then converting the result from km/h to km/min.
Step-by-step explanation:
To calculate the average velocity of the truck, we need to take the displacement (which is the truck's overall change in position) and divide that by the time taken for the trip. As the question specifies the truck travels east to west, and assuming it does not return, the displacement is the same as the distance traveled because these are in a straight line. The truck travels 15 km in 30 minutes. Since velocity is commonly expressed in hours, and there are 60 minutes in an hour, we need to convert 30 minutes into hours: 30 minutes = 0.5 hours.
The formula for average velocity is Vavg = displacement / time. Applying this to the given problem:
Vavg = 15 km / 0.5 h = 30 km/h.
However, the options A to D are given in km/min. To convert km/h to km/min, we divide by 60 (since there are 60 minutes in an hour). So, 30 km/h = 30 / 60 km/min = 0.5 km/min.
Thus, the correct option is A. 0.5 km/min.