ankur --
this may be a regional distinction -- perhaps english is structured differently in the country where you were educated -- but a single construction "twice of ..." would always be considered incorrect in american english.
the only way you're going to have "twice" next to "of" is when they're parts of completely different constructions; see #3 below.
basically, there are three different kinds of acceptable uses of "twice":
1)
twice NOUN/PRONOUN, where the noun or pronoun describes a numerical quantity of something;
2)
twice as ADV/ADJ (as)... /
twice this/that ADV/ADJ3)
twice by itself, meaning that something has happened two times (e.g.,
i've been there twice).
#3 is the only one of these constructions in which you might see "twice" followed by "of" -- and then only if they're independent constructions.
for instance, you could say
smith has already been advised twice of the foolishness of these actions.... notice that this construction is NOT "twice of"; the "of" is part of the boldfaced construction, but the "twice" is not.
note that, in #1, there may be possessives and/or adjectives in front of the NOUN.
--
your examples:
Usage : X is twice that Y
this isn't a construction.
you're only going to have "twice that..." in one of the following 2 cases:
1) "that" is a
relative pronoun (e.g.,
the unemployment rate of Country X is twice that of Country Y)
2) they're part of independent constructions (e.g.,
smith has already been advised twice that these actions are foolish)
1)The total money i have is twice that you have.
incorrect -- this "that" is not a relative pronoun such as the one above.
2)The total money i have is twice of what you have.
3)the total money i have is twice of that you have.
both incorrect -- "twice of X" is never correct as a single construction.
4)the total money i have is twice as much as you have.
"twice as much as you have" is ok.
"total money" isn't, though; you'd have to say "the amount of money" or "the total amount of money".
5)the total money i have is double of what you have.
incorrect -- the correct construction is "double X", not "double of X".
6)The number of books i have are twice that you have.
incorrect, same reason as #1
also, note that "the number ... are ..." is incorrect in all of these sentences; "the number" is singular, so the verb should be "is".
7)The number of books i have are twice as many as you have.
"twice as many as ..." is a correct construction.
you can't say "the
number is twice as
many", though -- that's a redundant construction.
you'd just say "i have twice as many books as you have."
8)the number of books i have are twice of as many as you have
wrong. can't have "twice of X".