It's quite common to be asked that question. It carries many unwanted contingencies. If you admit to approaching lots of girls and she thinks you do it because you only succeed with a small few of them, it will make you seem undesirable and like there is something wrong with her for being one of the small few who likes you.

On the flip side, if she thinks you both approach loads of girls and succeed with loads of them then she's going to be angry because girls generally want to be 1 in a million, not 1 of a million.

If you try and say you don't usually do it and she's the only one you've ever approached in the street then she could think you're a liar if she suspects you do it often and she may have reason to suspect that if you seemed very experienced and comfortable.

On the other hand if she believes she was the only one it might make her believe you were so instinctually attracted to her you just had to try your luck. This would put her in a position of having great power over you in her mind while you would know it isn't true and is just an illusion in her perception of the situation.

These are just a few philosophical insights into the nature of that question and situation. You might want to try and avoid each pitfall I've mentioned.

You could say you were listening to motivational talks to improve your work or business life and you decided to apply it in a dating context the day you saw her. That might give you some plausibility, reduce the chance of her thinking she was some sort of goddess, and stop her from thinking you're banging out large numbers of approaches on an on going basis.

While I have given an example of something you could say, it's often best to use your own judgement and creativity.

Hope that helps.

-Icy