At 10 a.m., Tammy and Cindy raced off together from the starting point of a track. Tammy ran at an average speed of 1 m/s. Cindy ran at an average speed of 2 m/s. Upon reaching the end of the track, Cindy rested for 4 minutes. She then immediately ran back along the same route at 2 m/s. At 10.40 a.m., Tammy met Cindy.

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 10.40 a.m. = 40 min

Duration that Tammy ran = 40 min
Duration that Cindy ran = 40 -  4 = 36 min

1 min = 60 s

36 min = 36 x 60 = 2160 s
40 min = 40 x 60 = 2400 s

Distance that Tammy ran
= 1 x 2400
= 2400 m

Distance that Cindy ran
= 2 x 2160
= 4320 m

Distance that Tammy and Cindy ran
= 2400 + 4320
= 6720 m

1000 m = 1 km

6720 m = 6720 ÷ 1000 = 6.72 km

(b)
Length of the trail
= 6.72 ÷ 2
= 3.36 km

Answer(s): (a) 6.72 km; (b) 3.36 km