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CUET · MATHS · PYQ PAPER 2025

A boat 10 m high floating at a uniform speed of 13 meters per minute \(( m / min )\) away from a lamp post 15 m high.
Then the rate at which the length of shadow of the boat increases is :

  1. A 26 m/min
  2. B 13 m/min
  3. C 52 m/min
  4. D 6.5 m/min
Verified Solution

Answer & Solution

Correct Answer

(A) 26 m/min

Step-by-step Solution

Detailed explanation

\( \frac{15}{x + L} = \frac{10}{L} \) \( 15L = 10(x + L) \) \( 5L = 10x \) \( L = 2x \) \( \frac{dL}{dt} = 2 \frac{dx}{dt} \) \( \frac{dL}{dt} = 2 \times 13 \) \( \frac{dL}{dt} = 26 \, m/min \)