One laptop seller is planning to increase the price/laptop by BDT 10,000 from the next month. Market research shows that with this increase in price he will be able to sell 6 fewer laptops in the next month but the total revenue will increase by BDT 32,000 to BDT 760,000. What is the number of laptops the seller will sell in the next month at this new price?

Explanation: Revenue = Price × Quantity. So, Price = \(\frac{\text{Revenue}}{\text{Quantity}}\). Now, \(\frac{\text{New revenue}}{\text{New quantity}} - \frac{\text{Old revenue}}{\text{Old quantity}} = 10,000\). \(\Rightarrow \frac{760,000}{q-6} - \frac{728,000}{q} = 10,000\); [let, old quantity of laptops be q]. \(\Rightarrow \frac{760}{q-6} - \frac{728}{q} = 10\). After this point, it is easier to test out the values from the options rather than solving the equation. The number 26 from option (C) solves the equation. So, that is the old quantity of laptops. Therefore, number of laptops that will be sold next month = \(26-6=20\).