At 8 a.m., Irene and Tammy raced off together from the starting point of a course. Irene ran at an average speed of 1 m/s. Tammy ran at an average speed of 4 m/s. Upon reaching the end of the course, Tammy rested for 6 minutes. She then immediately ran back along the same route at 4 m/s. At 8.30 a.m., Irene met Tammy.

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 8.30 a.m. = 30 min

Duration that Irene ran = 30 min
Duration that Tammy ran = 30 -  6 = 24 min

1 min = 60 s

24 min = 24 x 60 = 1440 s
30 min = 30 x 60 = 1800 s

Distance that Irene ran
= 1 x 1800
= 1800 m

Distance that Tammy ran
= 4 x 1440
= 5760 m

Distance that Irene and Tammy ran
= 1800 + 5760
= 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