Correct Answer: 13.7

Solution : Given: Sourav bought 30 kg of rice at Rs. 10 per kg and 35 kg at Rs. 11 per kg.
The total cost price (CP),
CP = 30 × 10 + 35 × 11 = 300 + 385 = Rs. 685
The total weight of the rice = 30 + 35 = 65 kg
Sourav wants to make a 30% profit on the total cost.
The total selling price (SP),
⇒ SP = CP + $\frac{30}{100}$ × CP = 685 + 0.3 × 685 = Rs. 890.5
The price per kg he should sell the mixture at to make a 30% profit = $\frac{890.5}{65}$ = Rs. 13.7
Hence, the correct answer is 13.7.