At 11 a.m., Olivia and Cindy raced off together from the starting point of a course. Olivia ran at an average speed of 3 m/s. Cindy ran at an average speed of 4 m/s. Upon reaching the end of the course, Cindy rested for 4 minutes. She then immediately ran back along the same route at 4 m/s. At 11.50 a.m., Olivia met Cindy.
- 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 11 a.m. to 11.50 a.m. = 50 min
Duration that Olivia ran = 50 min
Duration that Cindy ran = 50 - 4 = 46 min
1 min = 60 s
46 min = 46 x 60 = 2760 s
50 min = 50 x 60 = 3000 s
Distance that Olivia ran
= 3 x 3000
= 9000 m
Distance that Cindy ran
= 4 x 2760
= 11040 m
Distance that Olivia and Cindy ran
= 9000 + 11040
= 20040 m
1000 m = 1 km
20040 m = 20040 ÷ 1000 = 20.04 km
(b)
Length of the trail
= 20.04 ÷ 2
= 10.02 km
Answer(s): (a) 20.04 km; (b) 10.02 km