At 7 a.m., Linda and Vanessa raced off together from the starting point of a course. Linda 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 course, Vanessa rested for 5 minutes. She then immediately ran back along the same route at 4 m/s. At 7.25 a.m., Linda 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 7.25 a.m. = 25 min

Duration that Linda ran = 25 min
Duration that Vanessa ran = 25 -  5 = 20 min

1 min = 60 s

20 min = 20 x 60 = 1200 s
25 min = 25 x 60 = 1500 s

Distance that Linda ran
= 3 x 1500
= 4500 m

Distance that Vanessa ran
= 4 x 1200
= 4800 m

Distance that Linda and Vanessa ran
= 4500 + 4800
= 9300 m

1000 m = 1 km

9300 m = 9300 ÷ 1000 = 9.3 km

(b)
Length of the trail
= 9.3 ÷ 2
= 4.65 km

Answer(s): (a) 9.3 km; (b) 4.65 km