At 8 a.m., Penelope and Tina raced off together from the starting point of a course. Penelope ran at an average speed of 1 m/s. Tina ran at an average speed of 4 m/s. Upon reaching the end of the course, Tina rested for 3 minutes. She then immediately ran back along the same route at 4 m/s. At 8.35 a.m., Penelope met Tina.

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 8.35 a.m. = 35 min

Duration that Penelope ran = 35 min
Duration that Tina ran = 35 -  3 = 32 min

1 min = 60 s

32 min = 32 x 60 = 1920 s
35 min = 35 x 60 = 2100 s

Distance that Penelope ran
= 1 x 2100
= 2100 m

Distance that Tina ran
= 4 x 1920
= 7680 m

Distance that Penelope and Tina ran
= 2100 + 7680
= 9780 m

1000 m = 1 km

9780 m = 9780 ÷ 1000 = 9.78 km

(b)
Length of the trail
= 9.78 ÷ 2
= 4.89 km

Answer(s): (a) 9.78 km; (b) 4.89 km