Stock Option Calculation

I received offer from company that just raised Series A round. I'm trying to determine a method of finding out how much my stock options are worth.

They gave me multiple offers with varying salaries at different options amounts. The problem is that they gave me the options in form of value rather than percentage. For example, 200,000 + 50K options.

I asked for what percent 50K is of the company, but (and yes I know it's not a good sign when a company doesn't share this) but said they can't tell me the percentage of the company the 40K would represent.

They did tell me the strike price (~.65 cents) and the valuation they raised after series A (50 million)

Does this mean that I can calculate my percentage of the company by dividing 50,000/50 million (0.1%)?

At least this is what I was thinking... but then I remembered (from startups I formed in past) that stock options usually come from an option pool (usually around 15-20% of a company).

I'm just trying to figure out the percent I would own (after the vesting). If I know that, I can play around with dilution estimates for future raises and acquisition hypotheticals