At 11 a.m., Rachel and Jane raced off together from the starting point of a path. Rachel ran at an average speed of 1 m/s. Jane ran at an average speed of 4 m/s. Upon reaching the end of the path, Jane rested for 5 minutes. She then immediately ran back along the same route at 4 m/s. At 11.40 a.m., Rachel met Jane.

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 Rachel ran = 40 min
Duration that Jane ran = 40 -  5 = 35 min

1 min = 60 s

35 min = 35 x 60 = 2100 s
40 min = 40 x 60 = 2400 s

Distance that Rachel ran
= 1 x 2400
= 2400 m

Distance that Jane ran
= 4 x 2100
= 8400 m

Distance that Rachel and Jane ran
= 2400 + 8400
= 10800 m

1000 m = 1 km

10800 m = 10800 ÷ 1000 = 10.8 km

(b)
Length of the trail
= 10.8 ÷ 2
= 5.4 km

Answer(s): (a) 10.8 km; (b) 5.4 km