Answer: The running speed of Elena is 5 miles/hour and this can be determined by using the formula of speed.
Step-by-step explanation:
A circular running track 1/4 is a mile long.
Elena runs on this track, completing each lap in 1/20 of an hour.
Speed formula is used to determine the speed of Elena. The formula of speed is given by:
----- (1)
where S is the speed, D is the distance and T is the time taken by Elena to run a circle.
Now, put the value of distance D and time T in the equation (1).
Speed = 5 miles/hour
Therefore, the running speed of Elena is 5 miles/hour.
For more information, refer to the link given below:
brainly.com/question/22610586
