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Answer:
it take 31.53 minutes to run the entire race
it take 6.3 minutes to run the 1 km
Step-by-step explanation:
A runner ran 2/3 of a 5 kilometer race in 21 minutes. They ran the entire race at a constant speed.
[tex]\frac{2}{3} \cdot 5= \frac{10}{3}[/tex]
3.33 km is covered in 21 minutes
So 5 km is covered in [tex]\frac{5 \cdot 21}{3.33}=31.53[/tex]minutes
it take 31.53 minutes to run the entire race
[tex] \frac{10}{3}[/tex] km is covered in 21 minutes
1 km is covered in [tex]\frac{21}{\frac{10}{3} } =6.3[/tex]
It takes to run the entire race is 31 minutes and 30 seconds and it takes to run 1 kilometer is 6 minutes and 18 seconds.
What is speed?
The distance covered by the particle or the body in an hour is called speed. It is a scalar quantity. It is the ratio of distance to time.
We know that the speed formula
[tex]\rm speed = \dfrac{distance}{time}[/tex]
A runner ran 2/3 of a 5 kilometers race in 21 minutes. They ran the entire race at a constant speed.
2/3 of 5 km is given as x
[tex]x = \dfrac{2}{3}* 5 = \dfrac{10}{3}[/tex]
Then the speed will be
[tex]\rm speed = \dfrac{\frac{10}{3}}{21} = \dfrac{10}{3*21} = \dfrac{10}{63}[/tex]
a. It takes to run the entire race will be
[tex]\rm Time = \dfrac{5}{ \frac{10}{63}} = \dfrac{63* 5 }{10} =31.5[/tex]
It takes to run the entire race is 31 minutes and 30 seconds.
B. It takes to run 1 kilometer will be
[tex]\rm Time = \dfrac{1}{ \frac{10}{63}} = \dfrac{63* 1}{10} = 6.3[/tex]
It takes to run 1 kilometer is 6 minutes and 18 seconds.
More about the speed link is given below.
https://brainly.com/question/7359669
