Mathematics · 2019
JEE Main · 10 April 2019, Shift 2 · Q72
A spherical iron ball of radius 10 cm is coated with a layer of ice of uniform thickness that melts at a rate of 50 cm^3 / min. When the thickness of…
A spherical iron ball of radius $\displaystyle 10$ cm is coated with a layer of ice of uniform thickness that melts at a rate of $\displaystyle 50 \mathrm{~cm}^3 / \mathrm{min}$. When the thickness of the ice is $\displaystyle 5$ cm, then the rate at which the thickness (in cm/min) of the ice decreases, is:
Official answer
(3)
$\displaystyle \frac{1}{18 \pi}$
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JEE Main 2019 Mathematics question, with the answer from NTA’s final answer key. Where our answers come from.