At 7 a.m., Vanessa and Risa raced off together from the starting point of a track. Vanessa ran at an average speed of 2 m/s. Risa ran at an average speed of 3 m/s. Upon reaching the end of the track, Risa rested for 6 minutes. She then immediately ran back along the same route at 3 m/s. At 7.45 a.m., Vanessa met Risa.

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 7.45 a.m. = 45 min

Duration that Vanessa ran = 45 min
Duration that Risa ran = 45 -  6 = 39 min

1 min = 60 s

39 min = 39 x 60 = 2340 s
45 min = 45 x 60 = 2700 s

Distance that Vanessa ran
= 2 x 2700
= 5400 m

Distance that Risa ran
= 3 x 2340
= 7020 m

Distance that Vanessa and Risa ran
= 5400 + 7020
= 12420 m

1000 m = 1 km

12420 m = 12420 ÷ 1000 = 12.42 km

(b)
Length of the trail
= 12.42 ÷ 2
= 6.21 km

Answer(s): (a) 12.42 km; (b) 6.21 km