Three successive discount on the marked price of an article turns out to be equivalent to a single discount of 19%. If the rates of the first and second discount are 10% and 4% respectively, then what is the rate of 3rd discount?

6.25%

Let three successive discounts are 10%, 4%, x%

equivalent discount for 10% & 4%

                = 10 + 4 - \(\frac{10 × 4}{100}\) = 13.6

equivalent discount for all three equals to 19%

              19 = 13.6 + x - \(\frac{13.6 × x}{100}\)

              19 = 13.6 + x - 0.136x

              0.864x = 5.4

                    x = 6.25