At 10 a.m., Ivory and Jean raced off together from the starting point of a track. Ivory ran at an average speed of 1 m/s. Jean ran at an average speed of 4 m/s. Upon reaching the end of the track, Jean rested for 4 minutes. She then immediately ran back along the same route at 4 m/s. At 10.45 a.m., Ivory 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 10 a.m. to 10.45 a.m. = 45 min

Duration that Ivory ran = 45 min
Duration that Jean ran = 45 -  4 = 41 min

1 min = 60 s

41 min = 41 x 60 = 2460 s
45 min = 45 x 60 = 2700 s

Distance that Ivory ran
= 1 x 2700
= 2700 m

Distance that Jean ran
= 4 x 2460
= 9840 m

Distance that Ivory and Jean ran
= 2700 + 9840
= 12540 m

1000 m = 1 km

12540 m = 12540 ÷ 1000 = 12.54 km

(b)
Length of the trail
= 12.54 ÷ 2
= 6.27 km

Answer(s): (a) 12.54 km; (b) 6.27 km