Answer:
Ok, we have a total of 26 letters, and we want to select 5 of them.
Of the 26 letters, 21 are consonants and 5 are vowels.
Suppose that we want to have the consonant in the first selection, so the probability of picking a consonant is equal to the quotient between the number of consonants and the total number of letters.
p = 21/26
now a letter has been selected, so in the set, we have 25 letters left.
In the next 4 selections, we must select vowels.
In the second selection the probability is:
p = 5/25
in the third, the prob is:
p = 4/24 (we already selected one vowel before, so now we only have 4 vowels)
The fourth selection:
p = 3/23
and the last selection:
p = 2/22
The total probability is equal to the product of all the individual proabilities, so we have:
P = (2/22)*(3/23)*(4/24)*(5/25)*(21/26)
Now, remember that we said that the consonant must be in the first place, but it can be in any of the five places, so if we add the permutations of the consonant letter we have:
P = 5*(2/22)*(3/23)*(4/24)*(5/25)*(21/26) = 0.0018
