At 11 a.m., Eva and Min raced off together from the starting point of a path. Eva ran at an average speed of 3 m/s. Min ran at an average speed of 4 m/s. Upon reaching the end of the path, Min rested for 5 minutes. She then immediately ran back along the same route at 4 m/s. At 11.35 a.m., Eva met Min.

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 11 a.m. to 11.35 a.m. = 35 min

Duration that Eva ran = 35 min
Duration that Min ran = 35 -  5 = 30 min

1 min = 60 s

30 min = 30 x 60 = 1800 s
35 min = 35 x 60 = 2100 s

Distance that Eva ran
= 3 x 2100
= 6300 m

Distance that Min ran
= 4 x 1800
= 7200 m

Distance that Eva and Min ran
= 6300 + 7200
= 13500 m

1000 m = 1 km

13500 m = 13500 ÷ 1000 = 13.5 km

(b)
Length of the trail
= 13.5 ÷ 2
= 6.75 km

Answer(s): (a) 13.5 km; (b) 6.75 km