At 11 a.m., Shannon and Gem raced off together from the starting point of a course. Shannon ran at an average speed of 3 m/s. Gem ran at an average speed of 4 m/s. Upon reaching the end of the course, Gem rested for 4 minutes. She then immediately ran back along the same route at 4 m/s. At 11.50 a.m., Shannon 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 11 a.m. to 11.50 a.m. = 50 min

Duration that Shannon ran = 50 min
Duration that Gem ran = 50 -  4 = 46 min

1 min = 60 s

46 min = 46 x 60 = 2760 s
50 min = 50 x 60 = 3000 s

Distance that Shannon ran
= 3 x 3000
= 9000 m

Distance that Gem ran
= 4 x 2760
= 11040 m

Distance that Shannon and Gem ran
= 9000 + 11040
= 20040 m

1000 m = 1 km

20040 m = 20040 ÷ 1000 = 20.04 km

(b)
Length of the trail
= 20.04 ÷ 2
= 10.02 km

Answer(s): (a) 20.04 km; (b) 10.02 km