At 10 a.m., Mary and Hazel raced off together from the starting point of a track. Mary ran at an average speed of 1 m/s. Hazel ran at an average speed of 2 m/s. Upon reaching the end of the track, Hazel rested for 4 minutes. She then immediately ran back along the same route at 2 m/s. At 10.50 a.m., Mary met Hazel.

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 Mary ran = 50 min
Duration that Hazel ran = 50 -  4 = 46 min

1 min = 60 s

46 min = 46 x 60 = 2760 s
50 min = 50 x 60 = 3000 s

Distance that Mary ran
= 1 x 3000
= 3000 m

Distance that Hazel ran
= 2 x 2760
= 5520 m

Distance that Mary and Hazel ran
= 3000 + 5520
= 8520 m

1000 m = 1 km

8520 m = 8520 ÷ 1000 = 8.52 km

(b)
Length of the trail
= 8.52 ÷ 2
= 4.26 km

Answer(s): (a) 8.52 km; (b) 4.26 km