In Hungary, I think it is/was taught that the depth of Mariana Trench is 11 034 metres. As I can see, it is a Soviet measurement in the 50s. Since we were under a Soviet oppression, I'm not surprised to know these. From my childhood up till now, I was a hundred percent sure that 11 034 metres is the exact depth of the Mariana Trench. I really want to read Usrin's point of view.
I made two mistakes during my tipping.
1. The ID number tipping was about the last 4 digits, despite this, I thought that the first digit can't be 0, and because of this, I took the average and gave the tip as 5500. Otherwise, I would have given 5000 +/- 1.
2. About the diameters around the Earth... oh my God, I forgot to multiply my head calculation by two...