How many vowels are there in a standard set ? How many consonants ?
Have a little think ? Are there 30 vowels ? 40 ? 50 ?
There are 42 vowels, and 56 consonants. (and 2 blanks).
That is a ratio of 3:4, which is very difficult to work out especially as the letters come out randomly.
One way to consider the ratio is a 50:50 ratio with a slight emphasis to consonants.