The runner has to race for 21km. she has to finish race before 1h 40min. what avarage speed she has to run to gain such goal?

The rate of the runner is 3.5 meters per second.

Step-by-step explanation:

To get this answer in meters per second, we first have to convert each of the terms into either meters or seconds. We can do that by multiplying by unit rates.

21 km * 1000 = 21,000 meters

1 hour * 3600 = 3,600 seconds

40 minutes * 60 = 2,400 seconds

Now we divide the meters by the total number of seconds to get the rate.

21,000 meters / (3,600 + 2,400) secs

21,000 meters / 6,000 secs

3.5 meters per second.

c. 4 1/4 pounds