Total number of possible outcomes = Total number of alphabets = 26
We know,
Probability of occurrence of an event = (Total number of favorable outcomes) / (Total number of outcomes)
(i) a vowel
Favorable outcomes are a, e, i, o, u
Total number of favorable outcomes = 5
Therefore, the probability that the letter is chosen is a vowel = 5/26
(ii) a consonant
Total number of consonant = 26 – 5 = 21
Therefore, the probability that the letter is chosen is a consonant = 21/26