Question

a researcher is studying the movement of a vehicle along a straight path. during a 4-hour period, the vehicle travels the following distances: 60 km in the first hour, 80 km in the second hour, 40 km in the third hour, and 20 km in the fourth hour.
what is the average speed of the vehicle for the entire 4-hour period?
use the formula below to calculate average speed.
average speed = \\(\frac{\text{total distance}}{\text{total time}}\\)
a. \\(\circ\\) 50 km/h
b. \\(\circ\\) 60 km/h
c. \\(\circ\\) 75 km/h
d. \\(\circ\\) 70 km/h

Explanation:

Step1: Find total distance

Assuming the second hour distance is 80 km (since the first is 60, third 40, fourth 20, likely typo). So total distance = 60 + 80 + 40 + 20 = 200 km.

Step2: Find total time

Total time is 4 hours (given).

Step3: Calculate average speed

Using formula \( \text{Average Speed} = \frac{\text{Total Distance}}{\text{Total Time}} \), so \( \frac{200}{4} = 50 \) km/h? Wait, no, maybe the second hour is 80? Wait, maybe original problem: first hour 60, second 80, third 40, fourth 20. Total distance: 60+80=140, 140+40=180, 180+20=200. Total time 4. 200/4=50? But option A is 50. Wait, maybe I misread. Wait, let's check again. Wait, maybe the second hour is 80? Let's recalculate.

Wait, maybe the original problem: first hour 60 km, second hour 80 km (maybe typo in image), third 40, fourth 20. So total distance: 60 + 80 + 40 + 20 = 200 km. Total time 4 hours. Average speed = 200 / 4 = 50 km/h. So option A.

Wait, but let's confirm. If total distance is 60+80+40+20=200, time 4, then 200/4=50. So answer is A.

Answer:

A. 50 km/h