At 10 a.m., Barbara and Gem raced off together from the starting point of a route. Barbara ran at an average speed of 2 m/s. Gem ran at an average speed of 4 m/s. Upon reaching the end of the route, Gem rested for 3 minutes. She then immediately ran back along the same route at 4 m/s. At 10.30 a.m., Barbara met Gem.

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 10.30 a.m. = 30 min

Duration that Barbara ran = 30 min
Duration that Gem 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 Barbara ran
= 2 x 1800
= 3600 m

Distance that Gem ran
= 4 x 1620
= 6480 m

Distance that Barbara and Gem ran
= 3600 + 6480
= 10080 m

1000 m = 1 km

10080 m = 10080 ÷ 1000 = 10.08 km

(b)
Length of the trail
= 10.08 ÷ 2
= 5.04 km

Answer(s): (a) 10.08 km; (b) 5.04 km