There is one simple possibility that has not been mentioned. Suppose the Chennai bunk meter was indicating x lits but actually filling in less. On the return trip, the meter at the Hosur bunk would have given the correct reading, say, x-1 lits. and the correct mileage woud be returned. Conclusion: Chennai bunk may have been cheating on the meter, with corresponding drop in calculated mileage.
I find a similar phenomenon with my Santro. As measured by the reading in the Mumbai bunk (King's circle garden, Matunga) I always get a mileage of 10.x km/lit. When filling at the Pune bunk I get 11.x or 12.x, both times doing 120-150 kmph on the Expressway. Note that Pune is at higher altitude and one climbs the Lonwawala ghats on the way to Pune. Doing speeds of up to 120 kmph from Pune to Mahabaleshwar gave me a mileage of 13 km/lit at the Mahableshwar bunk meter, despite the climb; obviously the lower speeds were vital here. I thought driving around in the heavier Mumbai traffic was the reason for the low mileage returned at the Mumbai bunk, but now I am convinced that the Mumbai bunk is cheating on the meter.
There are other possibilities, of course, as mentioned by others. Mileage is notoriously difficult to pin down and varies greatly depending on many factors. |