A single discount equivalent to the discount series of 20%, 10% and 5% is?

To find a single discount equivalent to the discount series of 20%, 10%, and 5%, you need to calculate it in the following way:

1. Convert each percentage to a decimal. So, 20% becomes 0.20, 10% becomes 0.10, and 5% becomes 0.05.

2. Calculate the equivalent single discount using the formula:

   1 - (1 - d1) * (1 - d2) * (1 - d3)

   where d1, d2, and d3 are the decimal equivalents of the discounts.

3. Substitute the values into the formula:

   1 - (1 - 0.20) * (1 - 0.10) * (1 - 0.05)

4. Calculate the value inside the brackets first:

   1 - (0.80 * 0.90 * 0.95)

5. Continue with the multiplication:

   1 - 0.684

6. Subtract to find the single equivalent discount:

   0.316 or 31.6%

So, a single discount equivalent to the discount series of 20%, 10%, and 5% is approximately 31.6%.