Inequalities — IBPS PO Reasoning
Inequalities are the most mechanical topic in the whole reasoning paper: no diagram, no cases to imagine, just a chain of symbols and one rule about when a relation carries through. IBPS asks 3–5 of them in Prelims and folds the coded version into Mains. Once you internalise the "common sign, unbroken chain" rule and the either–or pattern, these are 20-second marks with near-perfect accuracy — the kind of block that quietly lifts your sectional score.
1. What IBPS actually asks
- Direct inequalities: a statement like
A > B ≥ C = D < Eand two conclusions (e.g.A > D,B ≥ E) — mark which definitely follow. - Coded inequalities: symbols are redefined ("
P © Qmeans P ≥ Q;P % Qmeans P < Q…"). You decode to real symbols first, then it's a direct inequality. - The either–or pair: two conclusions that are individually uncertain but together exhaust the possibilities.
The five relations: > (greater), < (less), ≥ (greater or equal), ≤ (less or equal), = (equal).
2. The one golden rule: common sign, unbroken chain
A conclusion between two variables is definite only if you can trace an unbroken chain between them where all the inequality signs point the same way (all "greater" or all "less"), treating = as transparent.
A > B > C⇒A > C✓ (all>).A > B < C⇒ nothing between A and C — the chain breaks at B (signs oppose). This is the core trap.A ≥ B ≥ C⇒A ≥ C✓. ButA ≥ B = C⇒A ≥ C✓ (=passes through).
The strict-vs-equal subtlety: the result is strict (>) only if at least one strict > appears in the chain; if every link is ≥/=, the result is ≥.
A > B ≥ C⇒A > C(one strict link makes it strict).A ≥ B ≥ C⇒A ≥ C(no strict link ⇒≥, not>).
3. The either–or (complementary) case
When a single pair cannot be fixed as > or = alone, but the two given conclusions are complementary (e.g. A > D and A = D, or A ≥ D and A < D) and together cover all cases, the answer is "either follows".
The classic setup: A ≥ B gives, between A and B, either A > B or A = B. So if the two conclusions are exactly A > B and A = B, neither alone is definite but either–or holds. Requirements: same pair of variables, complementary signs, and together exhaustive.
The either–or only applies to a single, ambiguous pair produced by a
≥/≤. If the chain is broken (opposite signs), you get plain "does not follow", not either–or.
4. Coded inequalities (Mains)
The question redefines symbols: "P @ Q = P > Q; P # Q = P < Q; P $ Q = P ≥ Q; P & Q = P ≤ Q; P * Q = P = Q." Your only first step:
- Rewrite the whole statement in real symbols.
P @ Q # R $ S→P > Q < R ≥ S. - Then apply the common-sign rule exactly as for direct inequalities.
Never try to reason on the letters/symbols directly — decode, then solve. The coding is just a translation layer.
Solved examples
Q1. Statement: A > B ≥ C = D < E. Conclusions: (I) A > C (II) A > E.
Show explanation
Solution. (I) A > B ≥ C is an unbroken >/≥ chain with a strict link ⇒ A > C follows. (II) A … < E? Chain C = D < E reverses direction relative to A — broken ⇒ A > E does not follow. Only I.
Q2 (either–or). Statement: P ≥ Q = R. Conclusions: (I) P > R (II) P = R.
Show explanation
Solution. P ≥ Q = R ⇒ P ≥ R, i.e. either P > R or P = R. Neither alone is definite; together they are complementary and exhaustive. Either I or II follows.
Q3 (broken chain). Statement: M < N > O ≥ P. Conclusion: M < P.
Show explanation
Solution. M < N then N > O — signs oppose at N ⇒ no relation between M and O/P. Does not follow.
Q4 (coded). Code: X @ Y = X ≥ Y; X © Y = X < Y. Statement: A @ B @ C © D. Conclusion: A ≥ C.
Show explanation
Solution. Decode: A ≥ B ≥ C < D. A ≥ B ≥ C ⇒ A ≥ C follows (no strict link, so ≥).
6. The 20-second protocol
For every inequality question:
- (Coded only) rewrite in real symbols first.
- Locate the two variables in the conclusion and trace the chain between them.
- Same direction, unbroken? Yes ⇒ follows. Broken (opposite signs) ⇒ does not follow.
- Strict or equal? A
>anywhere in the chain ⇒ strict; all≥/=⇒≥. - If a single pair is ambiguous, check the other conclusion for a complementary partner → either–or.
