What single rate of discount is equivalent to the series of discounts: $13 \%, 23 \%, 25 \%$, and $28 \%$ ?

Answer = $\%$ (written as a percentage rounded to two decimal places)

Step 1 ：Let's start with an initial value of \(100\)

Step 2 ：Apply the first discount of \(13\%\), which gives us a new value of \(100 - (100 \times \frac{13}{100}) = 87\)

Step 3 ：Apply the second discount of \(23\%\), which gives us a new value of \(87 - (87 \times \frac{23}{100}) = 66.99\)

Step 4 ：Apply the third discount of \(25\%\), which gives us a new value of \(66.99 - (66.99 \times \frac{25}{100}) = 50.2425\)

Step 5 ：Apply the fourth discount of \(28\%\), which gives us a final value of \(50.2425 - (50.2425 \times \frac{28}{100}) = 36.1746\)

Step 6 ：The equivalent single rate of discount is the percentage decrease from the original value to the final value, which is \((100 - 36.1746) = 63.8254\%\)

Step 7 ：Rounded to two decimal places, the equivalent single rate of discount is \(\boxed{63.83\%}\)