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BANKERS TUTORIAL · IBPS & RRB · ORIGINAL PRACTICE & ANALYSIS

Practice & review: Quantity comparison with valid domains

Compare two computed quantities, preserve all allowed values and use bounds when possible, while checking whether unstated assumptions about signs or integer values are influencing the relation.

01 / 03Learn with a clear direction

2 min read Original learning material · Prepared 14 Oct 2026

The worked question on this page is original educational practice. It is not represented as a question from an official previous-year examination paper.

01 / UNDERSTANDING

Review the question

Create original paired quantities whose relation changes across a domain boundary. Ask what extra condition makes the relation definite, teaching the role of information rather than only selecting an option.

02 / UNDERSTANDING

The concept in context

Bounds can settle a comparison without fully solving both sides. However, squaring, multiplying or dividing an inequality requires attention to signs and possible zero values. A counterexample can reject an always-greater claim, while several examples supporting it still do not establish a universal result. Explain the domain condition on which the conclusion depends.

03 / UNDERSTANDING

A worked learning case

Original educational case. In an original comparison, Quantity A is x² and Quantity B is x for a positive x. If x=2, A exceeds B; if x=0.5, A is smaller. Positivity alone does not determine one relation. An added condition x>1 would change the conclusion, showing why the domain is essential rather than optional background.

ORIGINAL EDUCATIONAL PRACTICE

Try it before you check.

Original practice: For every real x > 1, compare x² with x.

Show the answer and reasoning

x² is greater than x.

Because x is positive and greater than one, multiplying x by x increases it. Algebraically, x² − x = x(x − 1), and both factors are positive, so the difference is positive. The domain matters: for a positive x below one, the relation would reverse, so it cannot be omitted from the explanation.

Two traps to watch for.

  • Assuming a positive variable must be at least one.
  • Treating one supporting numerical example as universal proof.

YOUR TOPIC-SPECIFIC LEARNING MAP

Learn from the attempt

  1. Write the domain before comparing.

  2. Look for boundary and counterexample values.

  3. State the condition making a relation definite.

Explain the idea, apply it to a new situation, then check what changed in your reasoning.

BANKERS TUTORIAL · SOURCE NOTES

Keep the source alongside your notes.

Official links provide subject context and authoritative reference material. This guide’s explanation, scenario and question are original Bankers Tutorial learning content.

  1. www.ibps.in https://www.ibps.in/
  2. www.ibps.in https://www.ibps.in/index.php/faq/

For IBPS & RRB preparation, check the current official notice before relying on changing dates, rules or examination requirements.

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