Answer:
0.42 meters/second
Explanation:
The total distance traveled by Mary is: 80 m + 125 m + 45 m = 250 m
We want the speed in meters/second, so we have to convert the 10 minutes elapsed during the trip into seconds. Then we need a conversion factor, 1 minute is equivalent to 60 seconds.
time = 10 minutes * (60 seconds/1 minute) = 600 seconds (notice that minute is cancelled because is multiplying and dividing)
Now, we can compute the average speed is as follows:
Average speed = total distance/time = 250 m/600 s = 0.42 m/s
