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Mathematics · 2022 · 2 marks
CBSE 2022 · Region 4 · Set 3 · Q3
Three friends A, B and C got their photograph clicked. Find the probability that B is standing at the central position, given that A is standing at…
Three friends A, B and C got their photograph clicked. Find the probability that B is standing at the central position, given that A is standing at the left corner.
Marking-scheme solution
\(\displaystyle E_{1}: B\) is standing at centre position \(\displaystyle E_{2}: A\) is standing at left corner
\[\begin{aligned}
P\left(E_{1} \mid E_{2}\right) & =\frac{P\left(E_{1} \cap E_{2}\right)}{P\left(E_{2}\right)} \\
& =\frac{\dfrac{1}{6}}{\dfrac{2}{6}}=\frac{1}{2}
\end{aligned}
\]
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CBSE Class 12 Mathematics past-paper question from the 2022 board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.