The Cost Price of watch B is 20% more than that of watch A, watches A and B were marked up by 50% and 40% respectively. Watch A was sold at a discount of 20% and watch B was sold at discount of 30%. If the SP of watch A was Rs 30 more than the SP of watch B, then what was the CP of watch B?

Let CP of A = x. Then CP of B = 1.2x. Marked price of A = 1.5x, sold at 20% discount, so SP of A = 1.5x × 0.8 = 1.2x. Marked price of B = 1.2x × 1.4 = 1.68x, sold at 30% discount, so SP of B = 1.68x × 0.7 = 1.176x. Given SP of A is Rs 30 more than SP of B: 1.2x = 1.176x + 30, so 0.024x = 30, x = 1250. CP of B = 1.2x = 1.2 × 1250 = Rs 1500. Since 1500 is not among the options, the answer is 'None of these'.