If a guy is hiv+ and has unprotected sex with a girl but pulls out what's the chances of her getting hiv also?

Probably lower but..: There can still be HIV in seminal fluid (or pre-cum), so there is still some risk with pulling out. Thus, the risk is likely lower than if there was ejaculation, but there is no certainty that the risk is zero. Thus, i would not necessarily recommend this strategy. The question you have to ask yourself is, are you willing to risk getting HIV infection with this strategy when it can be prevented?