i cant get the right answer which is 1/3. i keep getting 4/12 or 1/12.
Show us how you keep getting 4/12 or 1/12. Can not correct bad behaviors, if we do not know what you are doing. I will say, that one of the answers you "keep getting", is the right answer; it just hasn't been reduced. Both show us both of your methods that lead you to 4/12 or 1/12.