How much is a Arab?

Answer 1

if you mean Arab noun.

n.

1. A member of a Semitic people inhabiting Arabia, whose language and Islamic religion spread widely throughout the Middle East and northern Africa from the seventh century.
2. A member of an Arabic-speaking people.
3. An Arabian horse.

[French Arabe, from Latin Arabs, from Greek Araps, Arab-, from Arabic 'Arab.]

Arab Ar'ab adj.

then you have a problem with English language because as you see Arab is a member of a Semitic people inhabiting Arabia . in addition using two vowels after each other (a Arab) is considered as wrong use of grammatical use.