At 7 a.m., Usha and Jade raced off together from the starting point of a route. Usha ran at an average speed of 1 m/s. Jade ran at an average speed of 2 m/s. Upon reaching the end of the route, Jade rested for 5 minutes. She then immediately ran back along the same route at 2 m/s. At 7.45 a.m., Usha met Jade.

1. Find the total distance covered by the two runners when they met each other. Express your answer in km.
2. Find the length of the trail in km.

(a)
From 7 a.m. to 7.45 a.m. = 45 min

Duration that Usha ran = 45 min
Duration that Jade ran = 45 -  5 = 40 min

1 min = 60 s

40 min = 40 x 60 = 2400 s
45 min = 45 x 60 = 2700 s

Distance that Usha ran
= 1 x 2700
= 2700 m

Distance that Jade ran
= 2 x 2400
= 4800 m

Distance that Usha and Jade ran
= 2700 + 4800
= 7500 m

1000 m = 1 km

7500 m = 7500 ÷ 1000 = 7.5 km

(b)
Length of the trail
= 7.5 ÷ 2
= 3.75 km

Answer(s): (a) 7.5 km; (b) 3.75 km