At 11 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 2 m/s. Upon reaching the end of the course, Betty rested for 6 minutes. She then immediately ran back along the same route at 2 m/s. At 11.45 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 11 a.m. to 11.45 a.m. = 45 min
Duration that Diana ran = 45 min
Duration that Betty ran = 45 - 6 = 39 min
1 min = 60 s
39 min = 39 x 60 = 2340 s
45 min = 45 x 60 = 2700 s
Distance that Diana ran
= 1 x 2700
= 2700 m
Distance that Betty ran
= 2 x 2340
= 4680 m
Distance that Diana and Betty ran
= 2700 + 4680
= 7380 m
1000 m = 1 km
7380 m = 7380 ÷ 1000 = 7.38 km
(b)
Length of the trail
= 7.38 ÷ 2
= 3.69 km
Answer(s): (a) 7.38 km; (b) 3.69 km