At 10 a.m., Diana and Betty raced off together from the starting point of a course. Diana ran at an average speed of 1 m/s. Betty ran at an average speed of 4 m/s. Upon reaching the end of the course, Betty rested for 6 minutes. She then immediately ran back along the same route at 4 m/s. At 10.35 a.m., Diana met Betty.
- 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 10 a.m. to 10.35 a.m. = 35 min
Duration that Diana ran = 35 min
Duration that Betty ran = 35 - 6 = 29 min
1 min = 60 s
29 min = 29 x 60 = 1740 s
35 min = 35 x 60 = 2100 s
Distance that Diana ran
= 1 x 2100
= 2100 m
Distance that Betty ran
= 4 x 1740
= 6960 m
Distance that Diana and Betty ran
= 2100 + 6960
= 9060 m
1000 m = 1 km
9060 m = 9060 ÷ 1000 = 9.06 km
(b)
Length of the trail
= 9.06 ÷ 2
= 4.53 km
Answer(s): (a) 9.06 km; (b) 4.53 km