I know, from a human rights point of view, this is very problematic. But imagine, if only people who can really understand written text, who can calculate, who understand how legal system works, who have basics of logic could vote.
Of course, those tests shouldn't be that ambiguous, but if they were phrased a bit more clear, these would be very simple. At the same time, English has changed in the last 50 years. That phrasing might have been common back then.
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