At 8 a.m., Tammy and Yen raced off together from the starting point of a track. Tammy ran at an average speed of 1 m/s. Yen ran at an average speed of 2 m/s. Upon reaching the end of the track, Yen rested for 3 minutes. She then immediately ran back along the same route at 2 m/s. At 8.50 a.m., Tammy met Yen.

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 8 a.m. to 8.50 a.m. = 50 min

Duration that Tammy ran = 50 min
Duration that Yen ran = 50 -  3 = 47 min

1 min = 60 s

47 min = 47 x 60 = 2820 s
50 min = 50 x 60 = 3000 s

Distance that Tammy ran
= 1 x 3000
= 3000 m

Distance that Yen ran
= 2 x 2820
= 5640 m

Distance that Tammy and Yen ran
= 3000 + 5640
= 8640 m

1000 m = 1 km

8640 m = 8640 ÷ 1000 = 8.64 km

(b)
Length of the trail
= 8.64 ÷ 2
= 4.32 km

Answer(s): (a) 8.64 km; (b) 4.32 km