At 11 a.m., Shiyun and Zara raced off together from the starting point of a track. Shiyun ran at an average speed of 2 m/s. Zara ran at an average speed of 4 m/s. Upon reaching the end of the track, Zara rested for 6 minutes. She then immediately ran back along the same route at 4 m/s. At 11.25 a.m., Shiyun met Zara.
- 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 11.25 a.m. = 25 min
Duration that Shiyun ran = 25 min
Duration that Zara ran = 25 - 6 = 19 min
1 min = 60 s
19 min = 19 x 60 = 1140 s
25 min = 25 x 60 = 1500 s
Distance that Shiyun ran
= 2 x 1500
= 3000 m
Distance that Zara ran
= 4 x 1140
= 4560 m
Distance that Shiyun and Zara ran
= 3000 + 4560
= 7560 m
1000 m = 1 km
7560 m = 7560 ÷ 1000 = 7.56 km
(b)
Length of the trail
= 7.56 ÷ 2
= 3.78 km
Answer(s): (a) 7.56 km; (b) 3.78 km