At 7 a.m., Mary and Vanessa raced off together from the starting point of a path. Mary ran at an average speed of 3 m/s. Vanessa ran at an average speed of 4 m/s. Upon reaching the end of the path, Vanessa rested for 6 minutes. She then immediately ran back along the same route at 4 m/s. At 7.30 a.m., Mary 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 7 a.m. to 7.30 a.m. = 30 min

Duration that Mary ran = 30 min
Duration that Vanessa ran = 30 -  6 = 24 min

1 min = 60 s

24 min = 24 x 60 = 1440 s
30 min = 30 x 60 = 1800 s

Distance that Mary ran
= 3 x 1800
= 5400 m

Distance that Vanessa ran
= 4 x 1440
= 5760 m

Distance that Mary and Vanessa ran
= 5400 + 5760
= 11160 m

1000 m = 1 km

11160 m = 11160 ÷ 1000 = 11.16 km

(b)
Length of the trail
= 11.16 ÷ 2
= 5.58 km

Answer(s): (a) 11.16 km; (b) 5.58 km