For the same reason why we don't normally use LL for 100 or DD for 1000 instead we use C and M respectively in Roman numerals and so therefore it follows that VV is normally notated as X for 10.
VV=X (5+5=10)
The Roman numerals VV VVV can be simplified to X XV and converted into Hindu-Arabic numerals are 10 and 15 respectively.
vv[vv fd
I am not sure that I understand your question. Do you mean which of the two numerals V or D should not be repeated in a numeral? If that is you question then the answer is that neither of them should be repeated. V = 5, so VV would in theory = 10 but there is already a Roman numeral for 10, which is X. D = 500 and in theory DD would = 1000 but again there is an existing Roman numeral for 1000, which is M.
VV Capelle was created in 1930.
VV Noordwijk was created in 1933.
VV UNA was created in 1929.
VV Montfoort was created in 1946.
VV Katwijk was created in 1939.
VV Gemert was created in 1912.
VV Baronie was created in 1924.
v vjv vv vv i lovd blud volll