The word ‘STATIONARY’ is written as TATSOIYRAN in certain code. How is…
2023
The word ‘STATIONARY’ is written as TATSOIYRAN in certain code. How is ‘ADVANTAGES’ written in that code?
Answer: B. AVDATNSEGA — Concept A transposition code changes no letter of a word — it only changes where each letter sits, so the coded word always uses exactly the same collection…
- A.
AVDANSESGA
- B.
AVDATNSEGA
- C.
SEGATNAVDA
- D.
DVAANTGASE
- E.
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Correct answer: B
Concept
A transposition code changes no letter of a word — it only changes where each letter sits, so the coded word always uses exactly the same collection of letters as the original word. To identify such a code, number the letters of the plain word, trace where each coded letter came from, and look for runs of consecutive positions that have been written in reverse. Those runs are the blocks of the code, and the same block pattern is then applied to every other word of the same length.
Applying it to the given example
Number the letters of STATIONARY: S = 1, T = 2, A = 3, T = 4, I = 5, O = 6, N = 7, A = 8, R = 9, Y = 10.
Set the code TATSOIYRAN against those numbered letters and find a consistent assignment of source positions: T = 4, A = 3, T = 2, S = 1, O = 6, I = 5, Y = 10, R = 9, A = 8, N = 7. Because STATIONARY repeats the letters T and A, more than one labelling is arithmetically possible, so this is a consistent reading that must still be checked against the given code.
Those source positions form three descending runs — 4, 3, 2, 1, then 6, 5, then 10, 9, 8, 7. So the ten letters are split as 4 + 2 + 4 and each block is written backwards.
Block | Letters | Written backwards |
|---|---|---|
First four | STAT | TATS |
Middle two | IO | OI |
Last four | NARY | YRAN |
Joining the reversed blocks gives TATS + OI + YRAN = TATSOIYRAN, which is exactly the code given in the question, so the rule is confirmed.
Applying the same rule to ADVANTAGES
Block | Letters | Written backwards |
|---|---|---|
First four | ADVA | AVDA |
Middle two | NT | TN |
Last four | AGES | SEGA |
Joining the reversed blocks gives AVDA + TN + SEGA = AVDATNSEGA.
Cross-check
The same rule can be stated with pairs: reverse each pair of ADVANTAGES — (AD)(VA)(NT)(AG)(ES) becomes (DA)(AV)(TN)(GA)(SE) — then exchange the first pair with the second and the fourth with the fifth, leaving the middle pair where it is. That gives AV + DA + TN + SE + GA = AVDATNSEGA, the same string, so the two ways of describing the rule agree.
Reversing the whole word is a different rule and does not fit the example: STATIONARY reversed is YRANOITATS, not TATSOIYRAN. Reversing ADVANTAGES as a whole would give SEGATNAVDA.
Reversing each pair but leaving all five pairs in their original order is also a different rule: STATIONARY would then become TSTAOIANYR, not TATSOIYRAN.
Result: ADVANTAGES is written as AVDATNSEGA.