How much to charge as a freelancer with one year of experience

does anyone have any advice on my how much the following person should charge

- freelancer that subcontracts from a bigger agencies

- 1 year marketing experience

- solely responsible for SEO(audits, execution, reporting) still learning ofcourse

- does social media co-ordination

- occasional dev work/ ad hoc fixing stuff that no one else can figure out

the agency I subcontract from gives average 100 hours per month. for context I’m in the uk and they are in North America.

what would a fair and reasonable hourly rate be for this scope of work?