A shopkeeper normally allows a 10% discount on the mark price. During a sale season, he decides to give two more discounts, the first being at a rate of 50% of the original and the second at a rate of 40% of the first. What is the equivalent single discount percent?

16.21

Let the  marked price = 100

SP @ 10% discount = 90

Value of two more discounts = 10 × \(\frac{50}{100}\) = 5%

                               and, IInd = 5 × \(\frac{40}{100}\) = 2%

Selling price after all discounts = 90 × \(\frac{95}{100}\) × \(\frac{98}{100}\)

                                           = 83.79

                            Total Discount  = 100 - 83.79 = 16.21%