Restaurant Manager pay ?

Not even close. Depending on what the minimum wage is in your area, your hourly workers could make more money than you. Consider this:  $15/hr x 40 hrs = $600

10 hrs OT at time and a half (22.50) = $225.  Total gross wages for the week $825.

$825 x 52 weeks = $42,900.  What you are being offered for a management position with it's accompanying headaches if an insult.

Not to me, but I have no idea what you might find acceptable.

It looks low.  But also consider health insurance and other benefits.

But suppose you don't take this job.  Can you do better at the same or fewer hours?

No.  You're not even earning a minimum $15/hr at that rate.  A mgr should be getting twice that amount.

I did it for less than that back in 1986 and 1987

I could not get a higher paying job

The reason they work you 50 hours is because a 40 hour week would be much lower pay like $24k

Im guessing its an exempt position  particularly if you are the location manager and not an assistant

Assistants are usually given an hourly wage plus overtime which equals your agreed upon salary

Where I live min wage is 725 which for 50 hours including OT is 20735  31% lower than $30k

That works out to about 14.65/hr based on a 40-hour week.  Or a "real" hourly of about 11.54/hr if you are working 50 hours a week.

For most people that would not be worth it, however, you also need to look at things such as any benefits you may get.   If you get full Medical/Dental/401K, 30K/year may be better than a company that pays you 40K but doesn't provide benefits.  

30k a year? Uhh no