At 7 a.m., Zara and Kylie raced off together from the starting point of a track. Zara ran at an average speed of 3 m/s. Kylie ran at an average speed of 4 m/s. Upon reaching the end of the track, Kylie rested for 5 minutes. She then immediately ran back along the same route at 4 m/s. At 7.45 a.m., Zara met Kylie.

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 7.45 a.m. = 45 min

Duration that Zara ran = 45 min
Duration that Kylie ran = 45 -  5 = 40 min

1 min = 60 s

40 min = 40 x 60 = 2400 s
45 min = 45 x 60 = 2700 s

Distance that Zara ran
= 3 x 2700
= 8100 m

Distance that Kylie ran
= 4 x 2400
= 9600 m

Distance that Zara and Kylie ran
= 8100 + 9600
= 17700 m

1000 m = 1 km

17700 m = 17700 ÷ 1000 = 17.7 km

(b)
Length of the trail
= 17.7 ÷ 2
= 8.85 km

Answer(s): (a) 17.7 km; (b) 8.85 km