Q10. Perhaps there's a double edge to this question or perhaps the interviewer doesn't understand JAR minima. There is no cloudbase minima for a precision approach. There is a minimum RVR and a DA published, but no minimum cloudbase. So if the published RVR is 550m and the reported RVR is 500m but the cloudbase 200', there is no question - an approach ban is in force, unless you have already passed the FAF. But if the cloudbase is reported at 150' and the RVR 550m you can still make an approach. Why?
The RVR is unequivical. An observer cannot see any further based on the assumption he is using the same equipment as the pilot - the Mk1 eyeball! However, the cloudbase is measured mechanically by an optical instrument which records the first contact with visible moisture. But cloud is like fog, and we can see through fog to a greater or lesser degree. So the Mk1 eyeball at 200' in cloud may see enough of the bright runway lights penetrating the cloud to make a decision to land.