The marked price of a laptop is ₹65,000. The laptop is sold at a discount of 20%. !f a profit of 30% is made through the sale, then what is the cost price of the laptop?

₹40,000

        CP                    MP

      100 - D%           100 + P%

     100 - 20%           100 + 30%

         80                      130

130x = 65,000

then, 80x = ₹40,000