he had struggled quite adequately with geometry , and got a good grade ; but in arithmetics he was an absolute failure : he was not wise enough to solve questions about two drivers travelling one toward the other or about two irrigating pipes that are pumping water from a cubic pool of 500x5x500 inches , each in a diameter of 10 inches : how long would it take them to empty that pool , if their pumping capacity is 30 cubic meters per hours ? - and so on.. you know that kind of damned questions .