The answer is 0.21.
There are in total 40 tiles:
28 vowels + 12 consonants = 40 tiles.
To calculate the probability, we will use the multiplication rule which calculates the probability that both of two events will occur:
The first event: the probability of choosing a consonant: 12/40 (because there are 12 consonants out of 40 tiles). 12/40 = 3/10
The second event: the probability of choosing a vowel: 28/40 (because there are 28 vowels out of 40 tiles). 28/40 = 7/10
Thus, the probability of choosing a consonant and then a vowel.is:
12/40 × 28/40 = 3/10 × 7/10 = 0.3 × 0.7 = 0.21