At 10 a.m., Nora and Diana raced off together from the starting point of a path. Nora ran at an average speed of 2 m/s. Diana ran at an average speed of 4 m/s. Upon reaching the end of the path, Diana rested for 5 minutes. She then immediately ran back along the same route at 4 m/s. At 10.50 a.m., Nora met Diana.

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 10.50 a.m. = 50 min

Duration that Nora ran = 50 min
Duration that Diana 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 Nora ran
= 2 x 3000
= 6000 m

Distance that Diana ran
= 4 x 2700
= 10800 m

Distance that Nora and Diana ran
= 6000 + 10800
= 16800 m

1000 m = 1 km

16800 m = 16800 ÷ 1000 = 16.8 km

(b)
Length of the trail
= 16.8 ÷ 2
= 8.4 km

Answer(s): (a) 16.8 km; (b) 8.4 km