At 9 a.m., Natalie and Penelope raced off together from the starting point of a course. Natalie ran at an average speed of 1 m/s. Penelope ran at an average speed of 2 m/s. Upon reaching the end of the course, Penelope rested for 4 minutes. She then immediately ran back along the same route at 2 m/s. At 9.45 a.m., Natalie met Penelope.

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 9.45 a.m. = 45 min

Duration that Natalie ran = 45 min
Duration that Penelope ran = 45 -  4 = 41 min

1 min = 60 s

41 min = 41 x 60 = 2460 s
45 min = 45 x 60 = 2700 s

Distance that Natalie ran
= 1 x 2700
= 2700 m

Distance that Penelope ran
= 2 x 2460
= 4920 m

Distance that Natalie and Penelope ran
= 2700 + 4920
= 7620 m

1000 m = 1 km

7620 m = 7620 ÷ 1000 = 7.62 km

(b)
Length of the trail
= 7.62 ÷ 2
= 3.81 km

Answer(s): (a) 7.62 km; (b) 3.81 km