"Had I worked hard, I would have passed." This is the sentence you should use. Please, always use capital letters for "I". "Had I worked hard, I would have been passed." This is a little odd because you have a passive sentence. You've told us that passing was not up to you; somebody would have given you a 'pass'. We naturally say "to pass an exam", so the first sentence is your choice here.

had i worked hard i would have passed. Had i worked hard i would have been passed. What it all means is down to the conditional case. "if I had worked harder, I would have passed the exam. Had I worked harder, I would have passed the exam. Either case is correct. You are talking about the past, so it means that if conditions were different, the result would have been different. You would have passed! Present, past and Future are the basics in understanding conditional situations. Good Luck, and relax a lot! Theresa

The first sentence is correct. "Been" is the past participle form of the verb "to be". We do not say "I am passed the exam", therefore we do not say "I would have been passed". The verb "to pass" does not need the auxiliary (helper) verb "to be" normally, therefore it would be incorrect to use it here.

I think the fist one is correct- WOULD HAVE PASSED EXAM, the second one is incorrect, because have been passed is passive voice.