At 11 a.m., Penelope and Gwen raced off together from the starting point of a pathway. Penelope ran at an average speed of 1 m/s. Gwen ran at an average speed of 4 m/s. Upon reaching the end of the pathway, Gwen rested for 3 minutes. She then immediately ran back along the same route at 4 m/s. At 11.35 a.m., Penelope met Gwen.

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 11 a.m. to 11.35 a.m. = 35 min

Duration that Penelope ran = 35 min
Duration that Gwen 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 Gwen ran
= 4 x 1920
= 7680 m

Distance that Penelope and Gwen 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