At 9 a.m., Elyse and Jen raced off together from the starting point of a route. Elyse ran at an average speed of 1 m/s. Jen ran at an average speed of 4 m/s. Upon reaching the end of the route, Jen rested for 3 minutes. She then immediately ran back along the same route at 4 m/s. At 9.50 a.m., Elyse met Jen.

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 9.50 a.m. = 50 min

Duration that Elyse ran = 50 min
Duration that Jen ran = 50 -  3 = 47 min

1 min = 60 s

47 min = 47 x 60 = 2820 s
50 min = 50 x 60 = 3000 s

Distance that Elyse ran
= 1 x 3000
= 3000 m

Distance that Jen ran
= 4 x 2820
= 11280 m

Distance that Elyse and Jen ran
= 3000 + 11280
= 14280 m

1000 m = 1 km

14280 m = 14280 ÷ 1000 = 14.28 km

(b)
Length of the trail
= 14.28 ÷ 2
= 7.14 km

Answer(s): (a) 14.28 km; (b) 7.14 km