At 7 a.m., Penelope and Eva raced off together from the starting point of a track. Penelope ran at an average speed of 3 m/s. Eva ran at an average speed of 4 m/s. Upon reaching the end of the track, Eva rested for 3 minutes. She then immediately ran back along the same route at 4 m/s. At 7.40 a.m., Penelope met Eva.

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 Penelope ran = 40 min
Duration that Eva ran = 40 -  3 = 37 min

1 min = 60 s

37 min = 37 x 60 = 2220 s
40 min = 40 x 60 = 2400 s

Distance that Penelope ran
= 3 x 2400
= 7200 m

Distance that Eva ran
= 4 x 2220
= 8880 m

Distance that Penelope and Eva ran
= 7200 + 8880
= 16080 m

1000 m = 1 km

16080 m = 16080 ÷ 1000 = 16.08 km

(b)
Length of the trail
= 16.08 ÷ 2
= 8.04 km

Answer(s): (a) 16.08 km; (b) 8.04 km