At 7 a.m., Irene and Diana raced off together from the starting point of a pathway. Irene ran at an average speed of 2 m/s. Diana ran at an average speed of 4 m/s. Upon reaching the end of the pathway, Diana rested for 6 minutes. She then immediately ran back along the same route at 4 m/s. At 7.25 a.m., Irene met Diana.

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 7 a.m. to 7.25 a.m. = 25 min

Duration that Irene ran = 25 min
Duration that Diana ran = 25 -  6 = 19 min

1 min = 60 s

19 min = 19 x 60 = 1140 s
25 min = 25 x 60 = 1500 s

Distance that Irene ran
= 2 x 1500
= 3000 m

Distance that Diana ran
= 4 x 1140
= 4560 m

Distance that Irene and Diana ran
= 3000 + 4560
= 7560 m

1000 m = 1 km

7560 m = 7560 ÷ 1000 = 7.56 km

(b)
Length of the trail
= 7.56 ÷ 2
= 3.78 km

Answer(s): (a) 7.56 km; (b) 3.78 km