At 11 a.m., Hilda and Xuan raced off together from the starting point of a course. Hilda ran at an average speed of 1 m/s. Xuan ran at an average speed of 2 m/s. Upon reaching the end of the course, Xuan rested for 3 minutes. She then immediately ran back along the same route at 2 m/s. At 11.30 a.m., Hilda met Xuan.

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 11.30 a.m. = 30 min

Duration that Hilda ran = 30 min
Duration that Xuan ran = 30 -  3 = 27 min

1 min = 60 s

27 min = 27 x 60 = 1620 s
30 min = 30 x 60 = 1800 s

Distance that Hilda ran
= 1 x 1800
= 1800 m

Distance that Xuan ran
= 2 x 1620
= 3240 m

Distance that Hilda and Xuan ran
= 1800 + 3240
= 5040 m

1000 m = 1 km

5040 m = 5040 ÷ 1000 = 5.04 km

(b)
Length of the trail
= 5.04 ÷ 2
= 2.52 km

Answer(s): (a) 5.04 km; (b) 2.52 km