At 8 a.m., Irene and Vanessa raced off together from the starting point of a route. Irene ran at an average speed of 2 m/s. Vanessa ran at an average speed of 4 m/s. Upon reaching the end of the route, Vanessa rested for 4 minutes. She then immediately ran back along the same route at 4 m/s. At 8.45 a.m., Irene met Vanessa.

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 8 a.m. to 8.45 a.m. = 45 min

Duration that Irene ran = 45 min
Duration that Vanessa ran = 45 -  4 = 41 min

1 min = 60 s

41 min = 41 x 60 = 2460 s
45 min = 45 x 60 = 2700 s

Distance that Irene ran
= 2 x 2700
= 5400 m

Distance that Vanessa ran
= 4 x 2460
= 9840 m

Distance that Irene and Vanessa ran
= 5400 + 9840
= 15240 m

1000 m = 1 km

15240 m = 15240 ÷ 1000 = 15.24 km

(b)
Length of the trail
= 15.24 ÷ 2
= 7.62 km

Answer(s): (a) 15.24 km; (b) 7.62 km