At 11 a.m., Shiyun and Victoria raced off together from the starting point of a route. Shiyun ran at an average speed of 3 m/s. Victoria ran at an average speed of 4 m/s. Upon reaching the end of the route, Victoria rested for 3 minutes. She then immediately ran back along the same route at 4 m/s. At 11.25 a.m., Shiyun met Victoria.

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 11.25 a.m. = 25 min

Duration that Shiyun ran = 25 min
Duration that Victoria ran = 25 -  3 = 22 min

1 min = 60 s

22 min = 22 x 60 = 1320 s
25 min = 25 x 60 = 1500 s

Distance that Shiyun ran
= 3 x 1500
= 4500 m

Distance that Victoria ran
= 4 x 1320
= 5280 m

Distance that Shiyun and Victoria ran
= 4500 + 5280
= 9780 m

1000 m = 1 km

9780 m = 9780 ÷ 1000 = 9.78 km

(b)
Length of the trail
= 9.78 ÷ 2
= 4.89 km

Answer(s): (a) 9.78 km; (b) 4.89 km