Answer:
1350m
Explanation:
Let the distance ran by Denise, Farah and Elaine be D, F and E meters respectively.
From the given information,
D= ⅔(E +F) -----(1)
E= ½(D +F) -----(2)
Let's get rid of the fraction so the equations are much easier to work with.
From (1):
3D= 2(E +F) (Multiply both sides by 3)
3D= 2E +2F -----(3) (Expand)
From (2):
2E= D +F -----(4)
Substitute (4) into (3):
3D= D +F +2F
3D -D= 3F
2D= 3F
Given that Farah ran 360m, F= 360.
2D= 3(360)
2D= 1080
D= 1080 ÷2
D= 540
2E= D +F
2E= 540 +360
2E= 900
E= 900 ÷2
E= 450
Total distance the 3 girls ran
= D +F +E
= 540 +360 +450
= 1350m
Alternatively, you could start by substituting F= 360 to equations (1) and (2).