In a track meet, the 400-meter relay involves four runners, each running 100 m. In one track meet, the first runner finished in 15 s, the second in

Question

17 s, the third in 15 s, and the final runner in 13 s. What was the average speed of the runners? (1 point)
• 6.7 m/s
• 26.7 m/s
• 67 m/s
• 0.15 s/m

Answer 1

To calculate the average speed of the runners in a relay, we can use the formula for average speed:

\[ \text{Average speed} = \frac{\text{Total distance}}{\text{Total time}} \]

In this case, the total distance of the relay is 400 meters (4 runners x 100 meters each).

Next, we need to calculate the total time taken by all four runners:

• First runner: 15 s
• Second runner: 17 s
• Third runner: 15 s
• Fourth runner: 13 s

Now, add up the times:

\[ \text{Total time} = 15 , \text{s} + 17 , \text{s} + 15 , \text{s} + 13 , \text{s} = 60 , \text{s} \]

Now we can calculate the average speed:

\[ \text{Average speed} = \frac{400 , \text{m}}{60 , \text{s}} \approx 6.67 , \text{m/s} \]

Therefore, rounding to one decimal place, the average speed is approximately 6.7 m/s.

So, the correct answer is 6.7 m/s.