1. **State the problem:** Given the sequence of letters `C L R T B Q S M A P D I N F J K G Y X`, we remove all vowels and then find the 13th letter from the left end in the remaining sequence. 2. **Identify vowels:** The vowels in the English alphabet are `A, E, I, O, U`. In the sequence, vowels are `A` and `I`. 3. **Remove vowels from sequence:** Remove `A` and `I` from `C L R T B Q S M A P D I N F J K G Y X`. Remaining sequence is: `C L R T B Q S M P D N F J K G Y X`. 4. **Count letters and find the 13th from the left:** Counting letters: 1:C 2:L 3:R 4:T 5:B 6:Q 7:S 8:M 9:P 10:D 11:N 12:F 13:J 5. **Answer:** The 13th letter from the left after removing vowels is `J`. **Final answer: J**