Mathematics · 2021
JEE Main · 16 March 2021, Shift 1 · Q65
Consider three observations a, b and c such that b = a + c. If the standard deviation of a +2, b +2, c +2 is d, then which of the following is true?
Consider three observations $\displaystyle \mathrm{a}, \mathrm{b}$ and c such that $\displaystyle \mathrm{b}=\mathrm{a}+\mathrm{c}$. If the standard deviation of $\displaystyle \mathrm{a}+2, \mathrm{~b}+2, \mathrm{c}+2$ is d, then which of the following is true ?
Official answer
(1)
$\displaystyle b^2=3\left(a^2+c^2\right)-9 d^2$
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JEE Main 2021 Mathematics question, with the answer from NTA’s final answer key. Where our answers come from.