If in a list of all the alphabets, the alphabets at positions of multiples of five are replaced by digit 1 and the alphabets at positions of multiples of seven are replaced by digit 2. How many alphabets are left now?

The logic follows here is:

Total English Alphabets: 26

The multiples of 5 in an English Alphabets: 5, 10, 15, 20, and 25

The multiples of 7 in an English Alphabets: 7, 14, and 21

According to the English alphabet series and its positional value

Now, replace the multiples of 5 in an English alphabet series with symbols and multiples of 7 with digits.

So, 8 English alphabets are there which are either replaced by symbols or by digits.

The number of alphabets which are left = 26 - 8 = 18

Hence, the correct answer is 18.