At 9 a.m., Lucy and Gillian raced off together from the starting point of a course. Lucy ran at an average speed of 1 m/s. Gillian ran at an average speed of 2 m/s. Upon reaching the end of the course, Gillian rested for 5 minutes. She then immediately ran back along the same route at 2 m/s. At 9.25 a.m., Lucy met Gillian.

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 9.25 a.m. = 25 min

Duration that Lucy ran = 25 min
Duration that Gillian 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 Lucy ran
= 1 x 1500
= 1500 m

Distance that Gillian ran
= 2 x 1200
= 2400 m

Distance that Lucy and Gillian ran
= 1500 + 2400
= 3900 m

1000 m = 1 km

3900 m = 3900 ÷ 1000 = 3.9 km

(b)
Length of the trail
= 3.9 ÷ 2
= 1.95 km

Answer(s): (a) 3.9 km; (b) 1.95 km