If you added a lot of royal blue to hot pink would it make blue violet?

I assume this is paint you’re talking about? Try 4 parts hot pink with 2 or 3 parts royal blue. Add it in gradually, mixing as you go, until it looks right.

Of course it would, all other things being equal, i.e. this is paint you’re talking about, or dye, or what. It won’t work if you’re adding royal blue jelly beans to hot pink ones. Unless you stand waaaaaay back and squint.