At 11 a.m., Lucy and Erika raced off together from the starting point of a path. Lucy ran at an average speed of 1 m/s. Erika ran at an average speed of 3 m/s. Upon reaching the end of the path, Erika rested for 6 minutes. She then immediately ran back along the same route at 3 m/s. At 11.40 a.m., Lucy met Erika.

1. Find the total distance covered by the two runners when they met each other. Express your answer in km.
2. Find the length of the trail in km.

(a)
From 11 a.m. to 11.40 a.m. = 40 min

Duration that Lucy ran = 40 min
Duration that Erika ran = 40 -  6 = 34 min

1 min = 60 s

34 min = 34 x 60 = 2040 s
40 min = 40 x 60 = 2400 s

Distance that Lucy ran
= 1 x 2400
= 2400 m

Distance that Erika ran
= 3 x 2040
= 6120 m

Distance that Lucy and Erika ran
= 2400 + 6120
= 8520 m

1000 m = 1 km

8520 m = 8520 ÷ 1000 = 8.52 km

(b)
Length of the trail
= 8.52 ÷ 2
= 4.26 km

Answer(s): (a) 8.52 km; (b) 4.26 km