At 7 a.m., Shiyun and Gabby raced off together from the starting point of a path. Shiyun ran at an average speed of 1 m/s. Gabby ran at an average speed of 3 m/s. Upon reaching the end of the path, Gabby rested for 3 minutes. She then immediately ran back along the same route at 3 m/s. At 7.30 a.m., Shiyun met Gabby.

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 7 a.m. to 7.30 a.m. = 30 min

Duration that Shiyun ran = 30 min
Duration that Gabby 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 Shiyun ran
= 1 x 1800
= 1800 m

Distance that Gabby ran
= 3 x 1620
= 4860 m

Distance that Shiyun and Gabby ran
= 1800 + 4860
= 6660 m

1000 m = 1 km

6660 m = 6660 ÷ 1000 = 6.66 km

(b)
Length of the trail
= 6.66 ÷ 2
= 3.33 km

Answer(s): (a) 6.66 km; (b) 3.33 km