At 11 a.m., Eva and Kathy raced off together from the starting point of a pathway. Eva ran at an average speed of 3 m/s. Kathy ran at an average speed of 4 m/s. Upon reaching the end of the pathway, Kathy rested for 3 minutes. She then immediately ran back along the same route at 4 m/s. At 11.50 a.m., Eva met Kathy.

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 11.50 a.m. = 50 min

Duration that Eva ran = 50 min
Duration that Kathy 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 Eva ran
= 3 x 3000
= 9000 m

Distance that Kathy ran
= 4 x 2820
= 11280 m

Distance that Eva and Kathy ran
= 9000 + 11280
= 20280 m

1000 m = 1 km

20280 m = 20280 ÷ 1000 = 20.28 km

(b)
Length of the trail
= 20.28 ÷ 2
= 10.14 km

Answer(s): (a) 20.28 km; (b) 10.14 km