B's profit =₹ (1050 − 630) = ₹420 The ratio of A and B's capital = ratio of their profit = 630:420 = 3:2 Let B's capital = ₹\(x\) According to the condition, \(900:x = 3:2\) Or, \(\frac{900}{x} = \frac{3}{2}\) Then, \(3x = 900 × 2\) So, \(x = \frac{900 × 2}{3}\) Therefore, \(x = 600\) ∴ B's capital was ₹600.