At 10 a.m., Nora and Olivia raced off together from the starting point of a path. Nora ran at an average speed of 1 m/s. Olivia ran at an average speed of 2 m/s. Upon reaching the end of the path, Olivia rested for 5 minutes. She then immediately ran back along the same route at 2 m/s. At 10.25 a.m., Nora met Olivia.

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 10 a.m. to 10.25 a.m. = 25 min

Duration that Nora ran = 25 min
Duration that Olivia 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 Nora ran
= 1 x 1500
= 1500 m

Distance that Olivia ran
= 2 x 1200
= 2400 m

Distance that Nora and Olivia 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