Reasoning Methods
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Reasoning Methods

Series

Check in this order:

  1. difference;
  2. second difference;
  3. multiplication/division;
  4. alternating positions;
  5. squares, cubes, primes or Fibonacci;
  6. digit operations.

Example: 2, 6, 12, 20, 30 is n(n+1): 1×2, 2×3, 3×4, 4×5, 5×6.

Direction sense

Draw a coordinate cross:

  • north = +y;
  • east = +x;
  • south = −y;
  • west = −x.

Track net movement, not every turn emotionally. If a person goes 4 km north, 3 km east and 4 km south, their final position is 3 km east of the start.

Blood relations

Translate each statement into a small family tree. Do not try to hold it in prose.

Questions often test:

  • gender;
  • generation;
  • maternal vs paternal relation;
  • relation from another person's viewpoint.

Syllogisms

Use set diagrams:

  • All A are B: A is inside B.
  • No A are B: A and B do not overlap.
  • Some A are B: A and B overlap at least once.

Never assume the reverse of "All A are B." From "All coders are learners," it does not follow that all learners are coders.

Coding-decoding

Check whether the code changes:

  • alphabet positions;
  • word order;
  • letters within each word;
  • fixed shifts;
  • symbols for words;
  • number values.

Use at least two examples before deciding the rule.

Seating arrangement

  1. Draw slots first.
  2. Place fixed positions first: ends, middle, immediate neighbours.
  3. Convert "second to the left" carefully from the person's perspective.
  4. Use a table for circle arrangements; keep a chosen person at the top to remove rotational duplicates.
  5. Test answer options if the puzzle is long and options are specific.

Statement and conclusion

A conclusion follows only if it is forced by the given statement. Common traps:

  • a reasonable idea is not necessarily a logical conclusion;
  • "some" does not mean "all";
  • a cause may not be established from a correlation.

Data sufficiency

Do not solve the entire problem at first. Test whether statement I alone is sufficient, statement II alone is sufficient, then both together.

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