Overtime And Public Holidays For Retail Employees

[Zen]

I was wondering whether people who are employed at the front line of a retail shop in a large department store is entitled to additional pay if he works on a public holiday? I thought that working on a public holiday would be considered "normal" for retail employees but seems like i'm wrong?

Also, if the staff works from 10am - 8pm, with 1hr lunch break and 1 hr dinner break in between, is he considered working 8hrs or 10hrs?

So, if he works 20days per month at 7,000 baht per month, his daily rate is 350baht per day and his hourly rate is = ??........??