At 10 a.m., Betty and Esther raced off together from the starting point of a pathway. Betty ran at an average speed of 1 m/s. Esther ran at an average speed of 4 m/s. Upon reaching the end of the pathway, Esther rested for 6 minutes. She then immediately ran back along the same route at 4 m/s. At 10.50 a.m., Betty met Esther.

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 10.50 a.m. = 50 min

Duration that Betty ran = 50 min
Duration that Esther ran = 50 -  6 = 44 min

1 min = 60 s

44 min = 44 x 60 = 2640 s
50 min = 50 x 60 = 3000 s

Distance that Betty ran
= 1 x 3000
= 3000 m

Distance that Esther ran
= 4 x 2640
= 10560 m

Distance that Betty and Esther ran
= 3000 + 10560
= 13560 m

1000 m = 1 km

13560 m = 13560 ÷ 1000 = 13.56 km

(b)
Length of the trail
= 13.56 ÷ 2
= 6.78 km

Answer(s): (a) 13.56 km; (b) 6.78 km