Most months there are 20 work days. Two days of taxes would be roughly 10%. The 9.25 days would be around 46% effective tax rate.
Not knowing where the writer lives its hard to be accurate, but I’d say its between 9.25 and 11 days.
DpM vs. DpW
So my guess of a likely minimum is 40% (2 of 5) or 8 of 20.
You’re right! I used all the days in my calculation, not just work days! I’ll go with 7, instead of 9.25