At 9 a.m., Erika and Jean raced off together from the starting point of a route. Erika ran at an average speed of 1 m/s. Jean ran at an average speed of 2 m/s. Upon reaching the end of the route, Jean rested for 4 minutes. She then immediately ran back along the same route at 2 m/s. At 9.35 a.m., Erika 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 9.35 a.m. = 35 min
Duration that Erika ran = 35 min
Duration that Jean ran = 35 - 4 = 31 min
1 min = 60 s
31 min = 31 x 60 = 1860 s
35 min = 35 x 60 = 2100 s
Distance that Erika ran
= 1 x 2100
= 2100 m
Distance that Jean ran
= 2 x 1860
= 3720 m
Distance that Erika and Jean ran
= 2100 + 3720
= 5820 m
1000 m = 1 km
5820 m = 5820 ÷ 1000 = 5.82 km
(b)
Length of the trail
= 5.82 ÷ 2
= 2.91 km
Answer(s): (a) 5.82 km; (b) 2.91 km