Let the original price of 1 kg of rice be \(x\) rupees. Then the new price per kg is \(x + 1\) rupees. Previously, Mr. Nutubabu could buy \(\frac{600}{x}\) kg of rice for ₹600. Now, he can buy \(\frac{600}{x + 1}\) kg of rice for the same amount. According to the question: \[ \frac{600}{x} - \frac{600}{x + 1} = 1 \] \[ \Rightarrow \frac{600(x + 1) - 600x}{x(x + 1)} = 1 \Rightarrow \frac{600x + 600 - 600x}{x^2 + x} = 1 \Rightarrow \frac{600}{x^2 + x} = 1 \Rightarrow x^2 + x = 600 \Rightarrow x^2 + x - 600 = 0 \] Now factorizing: \[ x^2 + 25x - 24x - 600 = 0 \Rightarrow x(x + 25) - 24(x + 25) = 0 \Rightarrow (x + 25)(x - 24) = 0 \] So either \(x + 25 = 0 \Rightarrow x = -25\) [Not acceptable, as price can't be negative] Or, \(x - 24 = 0 \Rightarrow x = 24\) ∴ The original price of 1 kg of rice was ₹24.