At 9 a.m., Rachel and Betty raced off together from the starting point of a pathway. Rachel ran at an average speed of 2 m/s. Betty ran at an average speed of 3 m/s. Upon reaching the end of the pathway, Betty rested for 4 minutes. She then immediately ran back along the same route at 3 m/s. At 9.40 a.m., Rachel met Betty.

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 9 a.m. to 9.40 a.m. = 40 min

Duration that Rachel ran = 40 min
Duration that Betty ran = 40 -  4 = 36 min

1 min = 60 s

36 min = 36 x 60 = 2160 s
40 min = 40 x 60 = 2400 s

Distance that Rachel ran
= 2 x 2400
= 4800 m

Distance that Betty ran
= 3 x 2160
= 6480 m

Distance that Rachel and Betty ran
= 4800 + 6480
= 11280 m

1000 m = 1 km

11280 m = 11280 ÷ 1000 = 11.28 km

(b)
Length of the trail
= 11.28 ÷ 2
= 5.64 km

Answer(s): (a) 11.28 km; (b) 5.64 km