At 7 a.m., Betty and Jean raced off together from the starting point of a course. Betty ran at an average speed of 1 m/s. Jean ran at an average speed of 2 m/s. Upon reaching the end of the course, Jean rested for 6 minutes. She then immediately ran back along the same route at 2 m/s. At 7.40 a.m., Betty met Jean.

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 7.40 a.m. = 40 min

Duration that Betty ran = 40 min
Duration that Jean 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 Betty ran
= 1 x 2400
= 2400 m

Distance that Jean ran
= 2 x 2040
= 4080 m

Distance that Betty and Jean ran
= 2400 + 4080
= 6480 m

1000 m = 1 km

6480 m = 6480 ÷ 1000 = 6.48 km

(b)
Length of the trail
= 6.48 ÷ 2
= 3.24 km

Answer(s): (a) 6.48 km; (b) 3.24 km