Coding-Decoding and Blood Relations
Key Takeaways
- Coding-decoding questions should be translated into alphabet positions, direction of shift, grouping, or substitution before attempting the answer.
- Blood-relation questions become simpler when every phrase is drawn as a family tree instead of held in memory.
- Words such as only son, only daughter, husband, wife, paternal, and maternal control the exact relationship and must not be skipped.
- In RRB NTPC, the safest method is to solve from the speaker's point of view and then convert the final link to the person asked about.
Translation Before Answering
Coding-decoding and blood relations look different, but they test the same discipline: translate the language into a stable form before selecting an answer. In coding, the stable form may be alphabet positions, a substitution table, or word order. In blood relations, it is a family tree. If you try to solve either topic mentally from the sentence alone, one skipped word can change the answer.
RRB NTPC reasoning questions in this area are usually short. That is helpful for time, but it also means every word matters. A fixed shift, reverse order, hidden code, or phrase such as only daughter can decide the question. Under one-third negative marking, a half-read relation is not a safe attempt.
Coding-Decoding Toolkit
| Code type | What to check | Example of method |
|---|---|---|
| Fixed alphabet shift | Same movement for every letter | Convert A-Z to 1-26 and add or subtract |
| Alternating shift | Odd and even positions move differently | Mark positions 1, 2, 3, 4 under the word |
| Reverse plus shift | Word reverses, then letters change | Test reversal before testing shift |
| Number code | Letters map to digits or positions | Build a small mapping table |
| Word code | Whole words receive symbols | Use repeated words across statements |
| Symbol operation | Signs stand for operations | Replace symbols, then use BODMAS |
How to Decode Letters
Start with letter positions. If RAIL is changed into another four-letter code, write R18, A1, I9, L12. Then compare each original letter with its coded letter. If the movement is +2, R becomes T, A becomes C, I becomes K, and L becomes N. If the movement changes by position, such as +1, +2, +3, +4, write that above the letters and verify the full word.
Be careful with wraparound. If Y moves forward by three, it becomes B, because the alphabet restarts after Z. In a timed CBT, many candidates lose easy marks by stopping at Z or by counting Z as 27. Use a small mental loop: X, Y, Z, A, B. For backward movement, count the other way.
When a code uses numbers, do not assume alphabetical order until repeated evidence supports it. A word-code item may say red train late means pa ru mi and late bus red means mi to pa. The repeated words show the repeated codes. Build the dictionary from repetition rather than guessing from the first line.
Blood Relations: Draw the Tree
For blood relations, write generations as rows. Parents are one row above children. Siblings stay on the same row. Spouses connect sideways. Use M and F only when gender is certain. If gender is not stated, do not invent it. The exam often tests exactly this restraint.
The speaker matters. In a statement such as the son of my father's only child, start with my father. If the father has only one child and the speaker is that child, the phrase points back to the speaker. The son of that person is the speaker's son. Solving from the wrong person makes the relation flip.
Relation Words That Control Meaning
- Paternal means from the father's side.
- Maternal means from the mother's side.
- Only son means no other male child in that family unit.
- Only daughter means no other female child in that family unit.
- Brother or sister gives sibling relation, not necessarily age order.
- In-law relations require a marriage link, not a blood link.
Mixed Reasoning Strategy
Some RRB NTPC questions combine relation chains with coded names. For example, a family puzzle may use initials, or a coded sentence may include relationship words. Separate the two jobs. Decode the names first, then draw the tree. Or draw the tree with symbols first, then replace symbols with names. Do not try to solve both at the same time in your head.
A strong rough-work habit is to use short marks: + for male if known, - for female if known, horizontal lines for spouses, vertical lines for children, and a circle around the person asked about. Keep the diagram small enough to fit beside the question on scratch paper.
Practice Mix
Do not practise only one code type at a time for weeks. RRB NTPC mixes fixed shifts, substitutions, symbol operations, and relationship chains, so revision should mix them too. A useful drill set has one easy alphabet shift, one wraparound item, one word-code item, one symbol-operation item, and one blood-relation chain. Review the missed step, not only the answer, because the same error pattern returns with different names and letters.
Error Checks Before Marking
Before choosing an answer in coding, ask whether the same rule works for every letter or word. If one letter does not fit, the rule may be alternating, reversed, or not a letter-shift code at all. Before choosing an answer in blood relations, ask who is speaking and whose relation is being asked. The final answer may be from the speaker to another person, or from that person back to the speaker.
These topics are scoring because they use method more than memory. The candidate who writes a small map usually beats the candidate who rereads the sentence three times. In the RRB NTPC CBT, the goal is not to make the solution look elegant; it is to make it unambiguous before risking the penalty.
Meena says, Nikhil is the son of my father's only child. How is Nikhil related to Meena?