How is the Salary calculated for employees in CA for a minimum wage?

To answer the best way I can is to say that if you are paid by the hour, then it doesn't matter if there are more than 20 business days in a month. On the other hand the question asks about salary and that doesn't have a "hourly rate" per say as you're being paid X/year. In that case it is simply divided by 12 and gives you how much you would expect to get each month, prior to taxes.

As far as the last part goes, income tax is a percent. So the actual percent wouldn't change but if the amount the person earns is more, the tax will take more away in essence.

Let's say you have earned $20 and the income tax is 10% (just using for nice numbers). The amount you'll actually get is $18. But if you earn $30 over a given pay period then you'll be left with $27. The amount taken out of the pay check changes based on what you earned, the tax itself does not change.

I hope this is what you're looking for, if not, I hope it's a little helpful.

Minimum wage is an hourly calculation...if, for example, minimum wage is $8, your weekly salary would be $8 times the number of hours you worked - you cannot assume 40 hours per week standard. If you only worked 20 hours, your weekly income would be $8 x 20 = $160 before taxes. Many businesses are open more than 8 hours per day and more than 5 days a week (retail for example) so you just can't say 20 days a month.

Salary is a different animal. A salaried job exempts the job holder from things like overtime and is usually paid as a flat rate per year (i.e., $35,000 a year).

when there are more than 20 business days? Does the income before taxes changes every month for these kind of employees?