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

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 Gabby ran = 35 min
Duration that Sabrina ran = 35 -  4 = 31 min

1 min = 60 s

31 min = 31 x 60 = 1860 s
35 min = 35 x 60 = 2100 s

Distance that Gabby ran
= 1 x 2100
= 2100 m

Distance that Sabrina ran
= 4 x 1860
= 7440 m

Distance that Gabby and Sabrina ran
= 2100 + 7440
= 9540 m

1000 m = 1 km

9540 m = 9540 ÷ 1000 = 9.54 km

(b)
Length of the trail
= 9.54 ÷ 2
= 4.77 km

Answer(s): (a) 9.54 km; (b) 4.77 km