Mathematics · 2025
JEE Main · 23 January 2025, Shift 2 · Q15
A spherical chocolate ball has a layer of ice-cream of uniform thickness around it. When the thickness of the ice-cream layer is 1 cm, the ice-cream…
A spherical chocolate ball has a layer of ice-cream of uniform thickness around it. When the thickness of the ice-cream layer is $\displaystyle 1$ cm, the ice-cream melts at the rate of $\displaystyle 81 \mathrm{~cm}^3 / \mathrm{min}$ and the thickness of the ice-cream layer decreases at the rate of $\displaystyle \frac{1}{4 \pi} \mathrm{~cm} / \mathrm{min}$. The surface area (in $\displaystyle \mathrm{cm}^2$ ) of the chocolate ball (without the ice-cream layer) is :
Official answer
From NTA’s final answer key for this paper.
(4)
$\displaystyle 256 \pi$
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JEE Main 2025 Mathematics question, with the answer from NTA’s final answer key. Where our answers come from.