At 7 a.m., Zoe and Ivory raced off together from the starting point of a pathway. Zoe ran at an average speed of 1 m/s. Ivory ran at an average speed of 3 m/s. Upon reaching the end of the pathway, Ivory rested for 3 minutes. She then immediately ran back along the same route at 3 m/s. At 7.40 a.m., Zoe met Ivory.

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 7 a.m. to 7.40 a.m. = 40 min

Duration that Zoe ran = 40 min
Duration that Ivory ran = 40 -  3 = 37 min

1 min = 60 s

37 min = 37 x 60 = 2220 s
40 min = 40 x 60 = 2400 s

Distance that Zoe ran
= 1 x 2400
= 2400 m

Distance that Ivory ran
= 3 x 2220
= 6660 m

Distance that Zoe and Ivory ran
= 2400 + 6660
= 9060 m

1000 m = 1 km

9060 m = 9060 ÷ 1000 = 9.06 km

(b)
Length of the trail
= 9.06 ÷ 2
= 4.53 km

Answer(s): (a) 9.06 km; (b) 4.53 km