At 8 a.m., Cathy and Marion raced off together from the starting point of a course. Cathy ran at an average speed of 1 m/s. Marion ran at an average speed of 3 m/s. Upon reaching the end of the course, Marion rested for 6 minutes. She then immediately ran back along the same route at 3 m/s. At 8.30 a.m., Cathy met Marion.

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 8 a.m. to 8.30 a.m. = 30 min

Duration that Cathy ran = 30 min
Duration that Marion 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 Cathy ran
= 1 x 1800
= 1800 m

Distance that Marion ran
= 3 x 1440
= 4320 m

Distance that Cathy and Marion ran
= 1800 + 4320
= 6120 m

1000 m = 1 km

6120 m = 6120 ÷ 1000 = 6.12 km

(b)
Length of the trail
= 6.12 ÷ 2
= 3.06 km

Answer(s): (a) 6.12 km; (b) 3.06 km