Question 2
The city uses the letters in this table. Gray cells are consonants; white cells are vowels.
Each four-character identification code begins with a digit 0–9. Each of the other three characters must be a letter from the table; the second character must be a vowel and the last must be a consonant. Consider TAA8,5ATO,1UEK,3OOP,6KTS,9UTU,4AOG,3I9K,2OPR. How many are valid?
Each four-character identification code begins with a digit 0–9. Each of the other three characters must be a letter from the table; the second character must be a vowel and the last must be a consonant. Consider TAA8,5ATO,1UEK,3OOP,6KTS,9UTU,4AOG,3I9K,2OPR. How many are valid?