Rose's average speed for a 45km journey was 75km/h. She took 21 minutes for the first two thirds of her journey. What was her average speed for the last one third of the journey
+37101 Her TIME for the entire journey is given by Distance/Rate = Time
45km/(75 km/hr) = .6 hr = 36 minutes
She spent 21 minutes going the first 2/3 2/3 of 45 = 30 km
SO she spent 36min-21min = 15 minutes travelling the remaining 15 km
Rate = distance/time = 15km/15min=15km/.25hr= 60km/hr for the final 1/3 (15 km)
