Task

Write a program to perform a conversion of the old Russian measures of length to the metric system   (and vice versa).



It is an example of a linear transformation of several variables.



The program should accept a single value in a selected unit of measurement, and convert and return it to the other units:

vershoks, arshins, sazhens, versts, meters, centimeters and kilometers.



Also see

   Old Russian measure of length


ClearAll[units, ConvertRussianQuantities]
units = {"RussianVershoks", "RussianArshins", "RussianSazhens", "RussianVerstas", "Centimeters", "Meters", "Kilometers"};
ConvertRussianQuantities[q_Quantity] := UnitConvert[q, #] & /@ Select[units, QuantityUnit[q] != # &]
ConvertRussianQuantities[Quantity[1, "Vershoks"]]
ConvertRussianQuantities[Quantity[1, "Arshins"]]