2022-II-43 – Solving Master

Ans: B

The required probability

$\begin{array}{cl} = & \frac{3}{7} \times \frac{2}{7} + \frac{3}{7} \times \frac{3}{7} \times \frac{3}{7} \times \frac{2}{7} + \frac{3}{7} \times \frac{3}{7} \times \frac{3}{7} \times \frac{3}{7} \times \frac{3}{7} \times \frac{2}{7} + \dots \\ = & \frac{6}{49} \div (1 - \frac{9}{49}) \\ = & \frac{3}{20} \end{array}$

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