I appreciate you taking the time to respond. I do think the various homework problems are fair and pretty well designed. If 3 people have reviewed each submission, I would have expected to get some feedback besides you are passing. If it is a rigorous review process then you should be able to easily say what criteria were not met. I think there is also the perception that the roles you can complete homework for, correspond to a current job opening. The applicant has no idea what your hiring timeline is and it may take them a week or two to submit all of the required assignments.