At 11 a.m., Nicole and Emily raced off together from the starting point of a route. Nicole ran at an average speed of 1 m/s. Emily ran at an average speed of 2 m/s. Upon reaching the end of the route, Emily rested for 5 minutes. She then immediately ran back along the same route at 2 m/s. At 11.50 a.m., Nicole met Emily.

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 11 a.m. to 11.50 a.m. = 50 min

Duration that Nicole ran = 50 min
Duration that Emily ran = 50 -  5 = 45 min

1 min = 60 s

45 min = 45 x 60 = 2700 s
50 min = 50 x 60 = 3000 s

Distance that Nicole ran
= 1 x 3000
= 3000 m

Distance that Emily ran
= 2 x 2700
= 5400 m

Distance that Nicole and Emily ran
= 3000 + 5400
= 8400 m

1000 m = 1 km

8400 m = 8400 ÷ 1000 = 8.4 km

(b)
Length of the trail
= 8.4 ÷ 2
= 4.2 km

Answer(s): (a) 8.4 km; (b) 4.2 km