Help Needed with adsense in wordpress

Hi

I need help with a problem.

I am a newbie and don’t know anything about installing wordpress or site maintenance.

I’ve paid someone to install wordpress blogs for me so i can earn some money by using adsense (need to learn first that how to put adsense into wordpress). He did setup blogs but now i can see that google ads are running on my blogs. it means that he put his adsense codes into my site.

How can i remove his adsense codes with mine?

any help will be appreciated.

thanks
Dharma