A dealer purchases a radio set for Rs. 350 and spends Rs. 100 on its repair. He makes a profit of 40% by selling the radio. The selling price of the radio set is

Correct option is B

Given
Purchase price = ₹ 350
Repair cost = ₹ 100
Profit % = 40%

Formula Used
Total Cost Price (CP) = Purchase Price + Repair Cost
Selling Price (SP) = $$\text{CP} \times \left(1 + \frac{\text{Profit \%}}{100}\right)$$​​

Solution
Total CP = 350 + 100 = 450
​$$SP = 450 \times (1 + \frac{40}{100}) \\\ \\SP = 450 \times \frac{140}{100}\\\ \\SP = 45 \times 14 = 630$$​​

Final Answer
So the correct answer is (b)