In a certain coding language 'CHEMISTRY' is written as 'DGFLJRUQZ', then in…
2020
In a certain coding language 'CHEMISTRY' is written as 'DGFLJRUQZ', then in the same code 'GEOMETRY' will be written as:
- A.
HDPLFSSZ
- B.
HDLPFSXS
- C.
HLDPFSSX
- D.
HDPLFSSX
Attempted by 1 students.
Show answer & explanation
Correct answer: D
Concept: In an alphabet-shift coding-decoding question, every letter of the source word is moved a fixed number of steps forward or backward in the alphabet to produce its code. The shift need not be uniform across the word - it can follow a repeating pattern, such as alternating forward and backward moves by position - and the exact rule is always found by comparing the given word with its given code letter by letter, then applied unchanged to the new word.
Application: Compare CHEMISTRY with its code DGFLJRUQZ, position by position:
Position | Letter (CHEMISTRY) | Coded letter | Shift |
|---|---|---|---|
1 | C | D | +1 (forward) |
2 | H | G | -1 (backward) |
3 | E | F | +1 (forward) |
4 | M | L | -1 (backward) |
5 | I | J | +1 (forward) |
6 | S | R | -1 (backward) |
7 | T | U | +1 (forward) |
8 | R | Q | -1 (backward) |
9 | Y | Z | +1 (forward) |
The shift alternates strictly by position: an odd position (1st, 3rd, 5th, ...) moves one step forward in the alphabet, and an even position (2nd, 4th, 6th, ...) moves one step backward. Apply this same odd-forward / even-backward rule to GEOMETRY, position by position:
Position | Letter (GEOMETRY) | Shift | Coded letter |
|---|---|---|---|
1 | G | +1 (forward) | H |
2 | E | -1 (backward) | D |
3 | O | +1 (forward) | P |
4 | M | -1 (backward) | L |
5 | E | +1 (forward) | F |
6 | T | -1 (backward) | S |
7 | R | +1 (forward) | S |
8 | Y | -1 (backward) | X |
Reading the coded letters in order gives H, D, P, L, F, S, S, X.
Cross-check: Reversing the same alternating rule on that result - undoing the forward shift on odd positions and the backward shift on even positions - restores G, E, O, M, E, T, R, Y exactly, confirming the pattern holds in both directions.
Result: GEOMETRY is coded as HDPLFSSX.