A store owner offers a successive discount of $20\%$ followed by another discount of $10\%$. What is the single equivalent discount percentage? (Write only the numeric value, e.g. write 28 for 28%)

Step 1: Let the original price of the product be $P$.

• After a $20\%$ discount, the price is scaled by $1-0.20=0.80$:

• After a successive $10\%$ discount, the new price is scaled by $1-0.10=0.90$:

Step 2: The total discount fraction is:

Step 3: Expressed as a percentage:

So the single equivalent discount is $28\%$.