At 8 a.m., Tiffany and Olivia raced off together from the starting point of a route. Tiffany ran at an average speed of 3 m/s. Olivia ran at an average speed of 4 m/s. Upon reaching the end of the route, Olivia rested for 5 minutes. She then immediately ran back along the same route at 4 m/s. At 8.25 a.m., Tiffany met Olivia.

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 8.25 a.m. = 25 min

Duration that Tiffany ran = 25 min
Duration that Olivia ran = 25 -  5 = 20 min

1 min = 60 s

20 min = 20 x 60 = 1200 s
25 min = 25 x 60 = 1500 s

Distance that Tiffany ran
= 3 x 1500
= 4500 m

Distance that Olivia ran
= 4 x 1200
= 4800 m

Distance that Tiffany and Olivia ran
= 4500 + 4800
= 9300 m

1000 m = 1 km

9300 m = 9300 ÷ 1000 = 9.3 km

(b)
Length of the trail
= 9.3 ÷ 2
= 4.65 km

Answer(s): (a) 9.3 km; (b) 4.65 km