Question

how many of you (work) here since 2005

Answer 1

I don't know.....¡!!!!¡!!!!¡!!!!¡!!!!!¡!!!!!¡!!!!!
lol......
XD....

Answer 2

$\huge\color{red}{Hello!}$

$\bold{ANSWER:-}$ How many of you have worked here since 2005?

In this sentence, 'many' is used which indicates plural form. So, we use 'have' for plural forms.

And this sentence tells you that the action has started in the past and still continuing in the present. Therefore, the tense used is present perfect tense.

$\bf\huge\boxed{\boxed{\boxed{HOPE\:IT\:HELPS!}}}$