One of the writers of the early exam presented me with a question that went something like the following, although in diagram rather than description: There's an open water tank that measures 10' diameter and 10' tall. The tank is filled with 8' of water. What's the pressure at the bottom of the tank?
Of course, 8' seems like the obvious answer, but he calculated the volume of water, how much it weighed, then divided that by the area of the bottom of the tank and came up with answer that wasn't 8'. I mean, the math idea was right, just a mistake made in rounding or one of the steps due to over-complication. Anyway, it's part of the reason I was happy to volunteer with question writing.