You'll struggle to find this kind of thing in print any more, thanks to dumbing down. The questions come from a 1950s Grammar School maths book. You can probably find plenty of similar books dirt cheap on Ebay and they are ***MILES*** better than anything published today. In fact for any subject where the science is settled, I now *always* go for something written in the 30s, 40s & 50s. The clarity and precision of language was *way* better back then, too.