If i took two hits off of a marijuana joint this past sunday and am a rare occasion smoker, what are the odds a test will be positive today?

Might be OK: The half life of marijuana is is variable with a mean value of between 13-20 hours. It takes approximately 6 half lives for a drug to be eliminated from your system. 20*6/24=5 days. The marijuana will stay in your system for about 5 days. Take this opportunity and stay clean.

Chances are low: but depends entirely on what kind of test is being used, and how sensitive it is. Most tests report positives at 50 ng/ml of THC, and it is unlikely that two hits 5 days ago will trigger a positive, but also depends on how potent the marijuana was. Of more concern is that you likely knew you were subject to testing, but still took the hits. This may indicate a problem in judgement, risk-taking.