Speed Maths Question?

The answer to your tricky nice sugery question is as follows. a) 11AM - 9AM = 2 hours , so From s=vt , 60*2=120 Km , but we do not karen's time , so this is what we do for karen 90*t= 120 Km , therefore t = 1 hour 20 minutes or rather 80 min. Which indicates that he left at 9h40 am. b) Tjason - Tkaren over the remaining distance is 2hours - 1h20 = 40 min. hope you understand , farewell!....