At 9 a.m., Abi and Zoe raced off together from the starting point of a pathway. Abi ran at an average speed of 3 m/s. Zoe ran at an average speed of 4 m/s. Upon reaching the end of the pathway, Zoe rested for 5 minutes. She then immediately ran back along the same route at 4 m/s. At 9.35 a.m., Abi met Zoe.

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 9.35 a.m. = 35 min

Duration that Abi ran = 35 min
Duration that Zoe ran = 35 -  5 = 30 min

1 min = 60 s

30 min = 30 x 60 = 1800 s
35 min = 35 x 60 = 2100 s

Distance that Abi ran
= 3 x 2100
= 6300 m

Distance that Zoe ran
= 4 x 1800
= 7200 m

Distance that Abi and Zoe ran
= 6300 + 7200
= 13500 m

1000 m = 1 km

13500 m = 13500 ÷ 1000 = 13.5 km

(b)
Length of the trail
= 13.5 ÷ 2
= 6.75 km

Answer(s): (a) 13.5 km; (b) 6.75 km