At 10 a.m., Betty and Dana raced off together from the starting point of a path. Betty ran at an average speed of 1 m/s. Dana ran at an average speed of 4 m/s. Upon reaching the end of the path, Dana rested for 4 minutes. She then immediately ran back along the same route at 4 m/s. At 10.30 a.m., Betty met Dana.

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 10 a.m. to 10.30 a.m. = 30 min

Duration that Betty ran = 30 min
Duration that Dana ran = 30 -  4 = 26 min

1 min = 60 s

26 min = 26 x 60 = 1560 s
30 min = 30 x 60 = 1800 s

Distance that Betty ran
= 1 x 1800
= 1800 m

Distance that Dana ran
= 4 x 1560
= 6240 m

Distance that Betty and Dana ran
= 1800 + 6240
= 8040 m

1000 m = 1 km

8040 m = 8040 ÷ 1000 = 8.04 km

(b)
Length of the trail
= 8.04 ÷ 2
= 4.02 km

Answer(s): (a) 8.04 km; (b) 4.02 km