Data Inaccuracies

My drive home is a nightmare. There are only 2 road options to get home, and both of them are sheer hell with all the traffic. I decided to put a mathematical approach to illustrate my point:-

* Whereis tells me that my total trip is 19.38km and should take 19 mins. (Soooo naïve!)
* My first 11.67km took me 12 mins last night (whereis says 10... not bad considering there are roadworks on the way).
* The remaining 7.71 km took me 25 minutes!!!!

40% of my trip takes 68% of my travel time. Step aside Einstein..get back Stephen Hawkings! I can whinge mathematically!