At 11 a.m., Irene and Tiffany raced off together from the starting point of a pathway. Irene ran at an average speed of 1 m/s. Tiffany ran at an average speed of 4 m/s. Upon reaching the end of the pathway, Tiffany rested for 5 minutes. She then immediately ran back along the same route at 4 m/s. At 11.45 a.m., Irene met Tiffany.

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 11.45 a.m. = 45 min

Duration that Irene ran = 45 min
Duration that Tiffany ran = 45 -  5 = 40 min

1 min = 60 s

40 min = 40 x 60 = 2400 s
45 min = 45 x 60 = 2700 s

Distance that Irene ran
= 1 x 2700
= 2700 m

Distance that Tiffany ran
= 4 x 2400
= 9600 m

Distance that Irene and Tiffany ran
= 2700 + 9600
= 12300 m

1000 m = 1 km

12300 m = 12300 ÷ 1000 = 12.3 km

(b)
Length of the trail
= 12.3 ÷ 2
= 6.15 km

Answer(s): (a) 12.3 km; (b) 6.15 km