X is directly proportional to A² and A is inversely proportional to Y. If X is 97 when Y is 6, find X when Y is 2.

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Question

This question was previously asked in

RRB NTPC Graduate Level CBT-I Official Paper (Held On: 09 Jun, 2025 Shift 1)

Answer 1

Given:

X is directly proportional to A² and A is inversely proportional to Y.

X = 97 when Y = 6.

Find X when Y = 2.

Formula used:

Since X ∝ A² and A ∝ 1/Y, we have:

X ∝ (1/Y)²

X = k × (1/Y)², where k is the constant of proportionality.

Calculation:

X = 97 when Y = 6:

⇒ 97 = k × (1/6)²

⇒ 97 = k × 1/36

⇒ k = 97 × 36

⇒ k = 3492

Now, find X when Y = 2:

⇒ X = k × (1/2)²

⇒ X = 3492 × 1/4

⇒ X = 873

∴ The correct answer is option 2.

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