At 8 a.m., Nicole and Sarah raced off together from the starting point of a course. Nicole ran at an average speed of 1 m/s. Sarah ran at an average speed of 2 m/s. Upon reaching the end of the course, Sarah rested for 5 minutes. She then immediately ran back along the same route at 2 m/s. At 8.45 a.m., Nicole met Sarah.

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 8 a.m. to 8.45 a.m. = 45 min

Duration that Nicole ran = 45 min
Duration that Sarah ran = 45 -  5 = 40 min

1 min = 60 s

40 min = 40 x 60 = 2400 s
45 min = 45 x 60 = 2700 s

Distance that Nicole ran
= 1 x 2700
= 2700 m

Distance that Sarah ran
= 2 x 2400
= 4800 m

Distance that Nicole and Sarah ran
= 2700 + 4800
= 7500 m

1000 m = 1 km

7500 m = 7500 ÷ 1000 = 7.5 km

(b)
Length of the trail
= 7.5 ÷ 2
= 3.75 km

Answer(s): (a) 7.5 km; (b) 3.75 km