At 7 a.m., Kylie and Linda raced off together from the starting point of a route. Kylie ran at an average speed of 1 m/s. Linda ran at an average speed of 3 m/s. Upon reaching the end of the route, Linda rested for 5 minutes. She then immediately ran back along the same route at 3 m/s. At 7.40 a.m., Kylie met Linda.

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 Kylie ran = 40 min
Duration that Linda ran = 40 -  5 = 35 min

1 min = 60 s

35 min = 35 x 60 = 2100 s
40 min = 40 x 60 = 2400 s

Distance that Kylie ran
= 1 x 2400
= 2400 m

Distance that Linda ran
= 3 x 2100
= 6300 m

Distance that Kylie and Linda ran
= 2400 + 6300
= 8700 m

1000 m = 1 km

8700 m = 8700 ÷ 1000 = 8.7 km

(b)
Length of the trail
= 8.7 ÷ 2
= 4.35 km

Answer(s): (a) 8.7 km; (b) 4.35 km