Question

Select the correct answer
Mary starts from her house, walks 80 meters south, and stops to chat with her aunt on the sidewalk. After chatting for a few minutes, she walks
125 meters to the west to meet a friend and then walks 45 meters north with her friend to a cafe for lunch. Overall, she takes 10 minutes to do all
this. What is Mary's average speed?
O A 8 metersisecond
OB. 1.25 meters/second
C. 25 metersisecond
D. 4.5 metersisecond
OE. 0.42 meters/second
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Answer 1

Answer:

Mary's average speed is 0.42 meters/second.

Explanation:

Mary's total travel was 250 meters and the elapsed time was 10 minutes, equivalent to 600 seconds.

d = displacement = 80 meters + 125 meters + 45 meters = 250 meters                  

t = time = 10 minutes . 60 seconds/minute = 600 seconds

We can obtain now the average speed:

s = average speed = displacement / time = 250 meters / 600 seconds ≅ 0.4167 ≅ 0.42