just think of how much has changed in math and sci. then there writing/spelling/punc/ etc. things have changed so much. I would be a good chunk of the test would not even be correct today.
That's just it. Cords, rods, hands, etc are measurements rarely used today,except in a few specialized fields. 100 years ago, those were things a lot more people needed to know for daily transactions.
For someone today to know that 1 rod = 16.5 feet or 1/320th of a mile would be nothing more than trivia for a vast majority of the population because it will never be needed in practical life.
Knowledge changes. As we gain more knowledge and technology, certain things become less important or even obsolete.