At 9 a.m., Emily and Julie raced off together from the starting point of a track. Emily ran at an average speed of 2 m/s. Julie ran at an average speed of 3 m/s. Upon reaching the end of the track, Julie rested for 4 minutes. She then immediately ran back along the same route at 3 m/s. At 9.45 a.m., Emily met Julie.
- 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 9 a.m. to 9.45 a.m. = 45 min
Duration that Emily ran = 45 min
Duration that Julie ran = 45 - 4 = 41 min
1 min = 60 s
41 min = 41 x 60 = 2460 s
45 min = 45 x 60 = 2700 s
Distance that Emily ran
= 2 x 2700
= 5400 m
Distance that Julie ran
= 3 x 2460
= 7380 m
Distance that Emily and Julie ran
= 5400 + 7380
= 12780 m
1000 m = 1 km
12780 m = 12780 ÷ 1000 = 12.78 km
(b)
Length of the trail
= 12.78 ÷ 2
= 6.39 km
Answer(s): (a) 12.78 km; (b) 6.39 km