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A Question is given followed by two Statements I and II. Consider the Question and the Statements and mark the correct option.
Question : Two circles with radii \(p, q\) \((p > q)\) in cm touch externally, where \(p, q\) are natural numbers and each greater than 1. What is the value of \((p - q)\) ?
Statement-I : The sum of their areas is \(130\pi \text{ cm}^2\)
Statement-II : The distance between the centres of the two circles is 14 cm
Which one of the following is correct in respect of the above Question and the Statements ?

This question was previously asked in
CDS 1 2026 Maths Question Paper (12-Apr-2026)
The correct answer is
The Question can be answered by using both the Statements together, but cannot be answered using either Statement alone

Analyzing Statement Sufficiency for Circle Radii Problem

The core task is to find the value of \((p - q)\) for two externally touching circles with radii \(p\) and \(q\). Key conditions are \(p > q\), and both \(p, q\) are natural numbers greater than 1.

Statement I Analysis: Sum of Areas

Statement I gives the sum of the areas:

\(\pi p^2 + \pi q^2 = 130\pi \text{ cm}^2\)

Dividing by \(\pi\), we get:

\(p^2 + q^2 = 130\)

We look for natural number pairs \((p, q)\) where \(p > q > 1\) that satisfy this equation.

  • Possible pairs are \((11, 3)\) because \(11^2 + 3^2 = 121 + 9 = 130\). Here, \(p - q = 11 - 3 = 8\).
  • Another possible pair is \((9, 7)\) because \(9^2 + 7^2 = 81 + 49 = 130\). Here, \(p - q = 9 - 7 = 2\).

Since Statement I alone yields two different values for \((p - q)\), it is insufficient to answer the question.

Statement II Analysis: Distance Between Centers

Statement II states the distance between the centers is 14 cm. For circles touching externally, this distance is the sum of their radii:

\(p + q = 14\)

We list pairs \((p, q)\) satisfying \(p > q > 1\) and \(p + q = 14\).

  • \((12, 2) \implies p - q = 10\)
  • \((11, 3) \implies p - q = 8\)
  • \((10, 4) \implies p - q = 6\)
  • \((9, 5) \implies p - q = 4\)
  • \((8, 6) \implies p - q = 2\)

Statement II alone results in multiple possible values for \((p - q)\), hence it is insufficient.

Combined Analysis of Statements I and II

To answer the question, both statements must hold true simultaneously.

  1. Condition from Statement I: \(p^2 + q^2 = 130\). Possible pairs \((p, q)\) are \((11, 3)\) and \((9, 7)\).
  2. Condition from Statement II: \(p + q = 14\).

We check the pairs from Statement I against Statement II:

  • Pair \((11, 3)\): \(11 + 3 = 14\). This satisfies Statement II. The difference \(p - q = 11 - 3 = 8\).
  • Pair \((9, 7)\): \(9 + 7 = 16\). This does not satisfy Statement II (\(p + q = 14\)).

Only the pair \((11, 3)\) satisfies both conditions. This provides a unique value for \(p - q\), which is 8.

Therefore, the question can be answered only when both statements are used together.

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