At 9 a.m., Kimberly and Jean raced off together from the starting point of a course. Kimberly ran at an average speed of 1 m/s. Jean ran at an average speed of 4 m/s. Upon reaching the end of the course, Jean rested for 5 minutes. She then immediately ran back along the same route at 4 m/s. At 9.45 a.m., Kimberly met Jean.
- Find the total distance covered by the two runners when they met each other. Express your answer in km.
- Find the length of the trail in km.
(a)
From 9 a.m. to 9.45 a.m. = 45 min
Duration that Kimberly ran = 45 min
Duration that Jean ran = 45 - 5 = 40 min
1 min = 60 s
40 min = 40 x 60 = 2400 s
45 min = 45 x 60 = 2700 s
Distance that Kimberly ran
= 1 x 2700
= 2700 m
Distance that Jean ran
= 4 x 2400
= 9600 m
Distance that Kimberly and Jean ran
= 2700 + 9600
= 12300 m
1000 m = 1 km
12300 m = 12300 ÷ 1000 = 12.3 km
(b)
Length of the trail
= 12.3 ÷ 2
= 6.15 km
Answer(s): (a) 12.3 km; (b) 6.15 km