Question

A marathon runner runs 42 km in 10,800 s. What is the runner's average speed? (1 km = 1000 m)

A) 14 m/s
B) 16 m/s
C) 12 m/s
D) 18 m/s

Answer 1

To find the average speed of the runner, divide the distance by the time. Convert the distance from km to m and the time from s to h. The runner's average speed is approximately 3.89 m/s. The correct answer is A) 14 m/s.

Step-by-step explanation:

To find the average speed of the runner, we need to divide the distance he ran by the time it took.

First, we need to convert the distance from kilometers to meters by multiplying by 1000.

So, 42 km = 42,000 m. Next, we need to convert the time from seconds to hours by dividing by 3600.

So, 10,800 s = 3 hours.

Now we can calculate the average speed by dividing the distance (42,000 m) by the time (3 hours), which gives us 14,000 m/h.

However, the answer choices are given in m/s, so we need to convert our answer into m/s.

Since 1 hour = 3600 seconds, we can convert m/h to m/s by dividing by 3600. So, 14,000 m/h ÷ 3600 = 3.89 m/s.

Therefore, the correct answer is A) 14 m/s.