Answer:
[tex]y = x +2.5\,km[/tex]
Step-by-step explanation:
The equations for each runner are, respectively:
Marcia
[tex]x = 4\,km[/tex]
Tamara
[tex]y = x +2.5\,km[/tex]
Race length
[tex]s = \frac{4}{3}\cdot y[/tex]
The relationship between each runner is:
[tex]y = x +2.5\,km[/tex]