At 8 a.m., Betty and Lucy raced off together from the starting point of a track. Betty ran at an average speed of 1 m/s. Lucy ran at an average speed of 2 m/s. Upon reaching the end of the track, Lucy rested for 6 minutes. She then immediately ran back along the same route at 2 m/s. At 8.40 a.m., Betty met Lucy.
- 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 8 a.m. to 8.40 a.m. = 40 min
Duration that Betty ran = 40 min
Duration that Lucy ran = 40 - 6 = 34 min
1 min = 60 s
34 min = 34 x 60 = 2040 s
40 min = 40 x 60 = 2400 s
Distance that Betty ran
= 1 x 2400
= 2400 m
Distance that Lucy ran
= 2 x 2040
= 4080 m
Distance that Betty and Lucy ran
= 2400 + 4080
= 6480 m
1000 m = 1 km
6480 m = 6480 ÷ 1000 = 6.48 km
(b)
Length of the trail
= 6.48 ÷ 2
= 3.24 km
Answer(s): (a) 6.48 km; (b) 3.24 km