Problem Solving and Logical Reasoning
What this domain tests
Problem Solving and Logical Reasoning checks structured thinking: number and letter series, deductive arguments, ordering and seating puzzles, coding, and data interpretation. The aim is to find the rule or valid conclusion, not to guess from surface similarity.
Core rules
- For series, test differences, ratios, alternating rules, and squares/cubes; write the differences down.
- In deduction, use only the stated premises. Valid forms include modus ponens (P→Q, P, therefore Q) and modus tollens (P→Q, not Q, therefore not P).
- Invalid forms include affirming the consequent (P→Q, Q, therefore P) and denying the antecedent.
- For ordering puzzles, draw a line or table and place fixed items first.
- For 'must be true' questions, eliminate options that could be false under one valid arrangement.
Worked example
Series: 2, 6, 12, 20, 30, ? Differences are 4, 6, 8, 10. The differences rise by 2 each time, so the next difference is 12 and the next term is 30 + 12 = 42. A common wrong answer is 40, produced by doubling the previous term or by assuming a simple +10 step. Checking the second differences-2, 2, 2-confirms a quadratic pattern.
Traps
- Using outside knowledge instead of the passage or premises.
- Confusing 'some' with 'all'.
- Stopping at the first plausible rule without testing it on every term.
- Reversing a conditional: 'if P then Q' does not mean 'if Q then P'.