Final answer:
Jane's average speed is calculated by dividing the distance she ran (200 metres) by the time it took her (21.4 seconds), giving us an average speed of 9.3 m/s when rounded to one decimal place.
Step-by-step explanation:
Jane runs 200 metres in 21.4 seconds, and we want to work out her average speed in metres per second. To find average speed, we use the formula:
Speed = Distance ÷ Time
So, we divide her total distance run (200 metres) by the time taken (21.4 seconds):
Average Speed = 200 m ÷ 21.4 s = 9.3458 m/s
When rounded to one decimal place, Jane's average speed is 9.3 m/s.
This calculation involves simple arithmetic by dividing the numbers of each measured quantity to yield the computed quantity (Speed) and likewise dividing the units to yield the unit of the computed quantity (m/s). To check if the answer is reasonable, consider an Olympic-quality sprinter who can run 100 m in approximately 10 s, with an average speed of 10 m/s. Jane's speed is a bit less than this benchmark, which makes sense given her time is over 21 seconds.