At 10 a.m., Jen and Anna raced off together from the starting point of a course. Jen ran at an average speed of 1 m/s. Anna ran at an average speed of 3 m/s. Upon reaching the end of the course, Anna rested for 4 minutes. She then immediately ran back along the same route at 3 m/s. At 10.40 a.m., Jen met Anna.

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 10 a.m. to 10.40 a.m. = 40 min

Duration that Jen ran = 40 min
Duration that Anna 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 Jen ran
= 1 x 2400
= 2400 m

Distance that Anna ran
= 3 x 2160
= 6480 m

Distance that Jen and Anna ran
= 2400 + 6480
= 8880 m

1000 m = 1 km

8880 m = 8880 ÷ 1000 = 8.88 km

(b)
Length of the trail
= 8.88 ÷ 2
= 4.44 km

Answer(s): (a) 8.88 km; (b) 4.44 km