This is a dumbed down version of OBP since with some projections you don't get all the stats you need. I know it's not accurate, but it's not like projections are completely accurate anyway.

What I'm trying to figure out is walks. The simple formula is (Hits + BBs)/(ABs + BBs) = OBP. With one set of projectiona I have, they give me the Hits, ABs, and OBP, and I want to calculate BBs.

I've played with the formula, but it's been 20 years since I took math in high school and apparently I am more rusty than I thought. Can some give me the formula to figure out the BBs in this case knowing the other values?

BB = ?