At 9 a.m., Zara and Barbara raced off together from the starting point of a route. Zara ran at an average speed of 3 m/s. Barbara ran at an average speed of 4 m/s. Upon reaching the end of the route, Barbara rested for 6 minutes. She then immediately ran back along the same route at 4 m/s. At 9.30 a.m., Zara met Barbara.

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 9 a.m. to 9.30 a.m. = 30 min

Duration that Zara ran = 30 min
Duration that Barbara ran = 30 -  6 = 24 min

1 min = 60 s

24 min = 24 x 60 = 1440 s
30 min = 30 x 60 = 1800 s

Distance that Zara ran
= 3 x 1800
= 5400 m

Distance that Barbara ran
= 4 x 1440
= 5760 m

Distance that Zara and Barbara ran
= 5400 + 5760
= 11160 m

1000 m = 1 km

11160 m = 11160 ÷ 1000 = 11.16 km

(b)
Length of the trail
= 11.16 ÷ 2
= 5.58 km

Answer(s): (a) 11.16 km; (b) 5.58 km