2026.09.24 03:15
the cola riddle
A long time ago, I came up with and still use this math problem: 'A bottle of cola is one and a half liters. How many liters are in one and a half bottles of cola?'. It is good, for example, for asking kids in early primary school, and sometimes older ones, to see who is clever. It's nice because it is realistic, simple, but not trivial. You can easily calculate it by multiplying two fractions – once you realize you can calculate it by multiplying two fractions, and if you know how to multiply fractions. You can also solve it using common sense: 'one and a half is one and a half, half of one is a half, half of a half is a quarter, so...'. And you can even calculate it this way: 'if it were a one-liter bottle, then one and a half of it would be one and a half liters, and if it were a two-liter bottle, then one and a half of it would be three liters, but it is neither a one-liter nor a two-liter bottle, but exactly in the middle, so the result will be in the middle between one and a half and three, and what number is in the middle between one and a half and three? oh, it didn't get any easier at all, I'm starting over...'.
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