At 7 a.m., Zoe and Xandra raced off together from the starting point of a course. Zoe ran at an average speed of 3 m/s. Xandra ran at an average speed of 4 m/s. Upon reaching the end of the course, Xandra rested for 6 minutes. She then immediately ran back along the same route at 4 m/s. At 7.30 a.m., Zoe met Xandra.

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 7 a.m. to 7.30 a.m. = 30 min

Duration that Zoe ran = 30 min
Duration that Xandra ran = 30 -  6 = 24 min

1 min = 60 s

24 min = 24 x 60 = 1440 s
30 min = 30 x 60 = 1800 s

Distance that Zoe ran
= 3 x 1800
= 5400 m

Distance that Xandra ran
= 4 x 1440
= 5760 m

Distance that Zoe and Xandra ran
= 5400 + 5760
= 11160 m

1000 m = 1 km

11160 m = 11160 ÷ 1000 = 11.16 km

(b)
Length of the trail
= 11.16 ÷ 2
= 5.58 km

Answer(s): (a) 11.16 km; (b) 5.58 km