At 10 a.m., Joelle and Xuan raced off together from the starting point of a path. Joelle ran at an average speed of 3 m/s. Xuan ran at an average speed of 4 m/s. Upon reaching the end of the path, Xuan rested for 3 minutes. She then immediately ran back along the same route at 4 m/s. At 10.50 a.m., Joelle 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 10 a.m. to 10.50 a.m. = 50 min

Duration that Joelle ran = 50 min
Duration that Xuan ran = 50 -  3 = 47 min

1 min = 60 s

47 min = 47 x 60 = 2820 s
50 min = 50 x 60 = 3000 s

Distance that Joelle ran
= 3 x 3000
= 9000 m

Distance that Xuan ran
= 4 x 2820
= 11280 m

Distance that Joelle and Xuan ran
= 9000 + 11280
= 20280 m

1000 m = 1 km

20280 m = 20280 ÷ 1000 = 20.28 km

(b)
Length of the trail
= 20.28 ÷ 2
= 10.14 km

Answer(s): (a) 20.28 km; (b) 10.14 km