Aakash,

In Q10, Law of Total Probability, in compartment #3, I believe the math is not correct. You have 3 Rupees and 4 Paise coins. This would make the math for that part of the equation 1/4 * 3/7. You have 1/4 * 3/4 implying that Rupees make up 3 of 4 coins in the compartment rather than 3 of the 7. Assuming this change, the final answer would be approximately 0.39.