I like this girl but her (slutty) friend keeps hitting on me?

So, I started going to a jogging park a couple of weeks ago and there are these two girls(who are friends, let's call them A and B). So I find girl A really pretty and I like her a lot. I believe she likes me a little bit too. But the problem is, her friend girl B keeps hitting on me and after these 2 weeks of observation, I figured that this girl B is kind of a slut. I don't like her, at all. So, how can I go and talk girl A while she is with girl B and will it make girl A say no to me when I ask her out because her friend likes me? Or this slutty behaviour of girl B wouldn't be taken seriously by girl A?