Question

An encryption system operates as follows:
Step 1. Fix a number \(k(k \leq 26).\)
Step 2. For each word, swap the first k letters from the front with the last k letters from the end in reverse order. If a word contains less than 2k letters, write the entire word in reverse order.
Step 3. Replace each letter by a letter k spaces ahead in the alphabet. If you cross Z in the process to move k steps ahead, start again from A.
Example: k = 2: zebra --> arbez --> ctdgb.
If the word “flight” becomes “znmorl” after encryption, then the value of k:

• A. 5
• B. 4
• C. 7
• D. Cannot be determined uniquely from the given information
• E. 6

Answer 1

Answer: (E)

Step 1: Reverse operation understanding 
The word is flight and after encryption it becomes znmorl. We need to find k.

Step 2: Apply Step 2 of encryption (swapping)
The word length = 6. If k = 6, then 2k = 12 > 6. Therefore, by the given rule, we write the entire word in reverse. flight → thgilf.

Step 3: Apply Step 3 of encryption (shift letters by k)
Now shift each letter forward by k = 6 positions in the alphabet:

• t → z
• h → n
• g → m
• i → o
• l → r
• f → l

So, thgilf → znmorl, which matches the given result.

Step 4: Conclusion
Hence, the correct value of k is 6.

Final Answer: Option (5)