Jenny and Ella decide to make the most of their last weekend off before going their separate ways back to university.
As the weather is nice and they are both keen cyclists, they decide to complete a 50km challenge.
Both Jenny and Ella cycled along the same 50km route, but they complete it at different times.
Jenny took 2 1/2 hours to cycle the 50km.
Ella started to cycle 5 minutes after Jenny started to cycle.
Ella caught up with Jenny when they had both cycled 15km.
Jenny and Ella both cycled at constant speeds.
Work out Ella’s speed.
Answer:
S = D/T
Jenny’s speed = 50/ 2.5 = 20 km/ hr
So the time for Jenny to cycle 15 km would be:
T = D/S = 15/20 = 0.75 hr = 45 minutes (0.75 x 60)
So it would have taken Ella 40 minutes to cycle 15km (ie 45 – 5)
Therefore Ella’s speed = 15 / (40/60) = 22.5 km/hr