At 8 a.m., Yoko and Fiona raced off together from the starting point of a track. Yoko ran at an average speed of 2 m/s. Fiona ran at an average speed of 4 m/s. Upon reaching the end of the track, Fiona rested for 5 minutes. She then immediately ran back along the same route at 4 m/s. At 8.25 a.m., Yoko met Fiona.

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 8 a.m. to 8.25 a.m. = 25 min

Duration that Yoko ran = 25 min
Duration that Fiona ran = 25 -  5 = 20 min

1 min = 60 s

20 min = 20 x 60 = 1200 s
25 min = 25 x 60 = 1500 s

Distance that Yoko ran
= 2 x 1500
= 3000 m

Distance that Fiona ran
= 4 x 1200
= 4800 m

Distance that Yoko and Fiona ran
= 3000 + 4800
= 7800 m

1000 m = 1 km

7800 m = 7800 ÷ 1000 = 7.8 km

(b)
Length of the trail
= 7.8 ÷ 2
= 3.9 km

Answer(s): (a) 7.8 km; (b) 3.9 km