What is the probability that a letter picked at random is a vowel?

Answer 1

Well, consider that there are 26 letters in the alphabet. 5 of these are vowels (a, e, i, o and u).

Therefore the probability is 5/26 - or 0.192307692.

This assumes, of course, that you are randomly picking a letter from the alphabet... or rather, that each letter occurs in equal proportion within a larger text.

This assumes the English alphabet. In other alphabets from other languages, there may be a different quantity of vowels and a different quantity of consonants (or possibly other letters all together).

In writing, however, it is not the case that each letter appears in equal proportion. In a typical written document, for example, vowels make up about 38% of a text, on average. But it depends on a particular text, too, it may vary a little.

Of course, it matters which language you draw a text from. Those languages which use the exact same alphabet as in English dont necessarily have the same distribution of vowels in text.