At 9 a.m., Kathy and Jaslyn raced off together from the starting point of a course. Kathy ran at an average speed of 2 m/s. Jaslyn ran at an average speed of 4 m/s. Upon reaching the end of the course, Jaslyn rested for 5 minutes. She then immediately ran back along the same route at 4 m/s. At 9.25 a.m., Kathy met Jaslyn.

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 9 a.m. to 9.25 a.m. = 25 min

Duration that Kathy ran = 25 min
Duration that Jaslyn 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 Kathy ran
= 2 x 1500
= 3000 m

Distance that Jaslyn ran
= 4 x 1200
= 4800 m

Distance that Kathy and Jaslyn ran
= 3000 + 4800
= 7800 m

1000 m = 1 km

7800 m = 7800 ÷ 1000 = 7.8 km

(b)
Length of the trail
= 7.8 ÷ 2
= 3.9 km

Answer(s): (a) 7.8 km; (b) 3.9 km