At 9 a.m., Cathy and Esther raced off together from the starting point of a path. Cathy ran at an average speed of 2 m/s. Esther ran at an average speed of 4 m/s. Upon reaching the end of the path, Esther rested for 4 minutes. She then immediately ran back along the same route at 4 m/s. At 9.25 a.m., Cathy met Esther.

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 9 a.m. to 9.25 a.m. = 25 min

Duration that Cathy ran = 25 min
Duration that Esther ran = 25 -  4 = 21 min

1 min = 60 s

21 min = 21 x 60 = 1260 s
25 min = 25 x 60 = 1500 s

Distance that Cathy ran
= 2 x 1500
= 3000 m

Distance that Esther ran
= 4 x 1260
= 5040 m

Distance that Cathy and Esther ran
= 3000 + 5040
= 8040 m

1000 m = 1 km

8040 m = 8040 ÷ 1000 = 8.04 km

(b)
Length of the trail
= 8.04 ÷ 2
= 4.02 km

Answer(s): (a) 8.04 km; (b) 4.02 km