At 10 a.m., Erika and Abi raced off together from the starting point of a course. Erika ran at an average speed of 1 m/s. Abi ran at an average speed of 2 m/s. Upon reaching the end of the course, Abi rested for 6 minutes. She then immediately ran back along the same route at 2 m/s. At 10.45 a.m., Erika met Abi.

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 10 a.m. to 10.45 a.m. = 45 min

Duration that Erika ran = 45 min
Duration that Abi ran = 45 -  6 = 39 min

1 min = 60 s

39 min = 39 x 60 = 2340 s
45 min = 45 x 60 = 2700 s

Distance that Erika ran
= 1 x 2700
= 2700 m

Distance that Abi ran
= 2 x 2340
= 4680 m

Distance that Erika and Abi ran
= 2700 + 4680
= 7380 m

1000 m = 1 km

7380 m = 7380 ÷ 1000 = 7.38 km

(b)
Length of the trail
= 7.38 ÷ 2
= 3.69 km

Answer(s): (a) 7.38 km; (b) 3.69 km