At 10 a.m., Esther and Irene raced off together from the starting point of a path. Esther ran at an average speed of 3 m/s. Irene ran at an average speed of 4 m/s. Upon reaching the end of the path, Irene rested for 3 minutes. She then immediately ran back along the same route at 4 m/s. At 10.35 a.m., Esther met Irene.

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 10.35 a.m. = 35 min

Duration that Esther ran = 35 min
Duration that Irene ran = 35 -  3 = 32 min

1 min = 60 s

32 min = 32 x 60 = 1920 s
35 min = 35 x 60 = 2100 s

Distance that Esther ran
= 3 x 2100
= 6300 m

Distance that Irene ran
= 4 x 1920
= 7680 m

Distance that Esther and Irene ran
= 6300 + 7680
= 13980 m

1000 m = 1 km

13980 m = 13980 ÷ 1000 = 13.98 km

(b)
Length of the trail
= 13.98 ÷ 2
= 6.99 km

Answer(s): (a) 13.98 km; (b) 6.99 km