A store owner paid $20 for a book. She marked up the price of the book by 15% to determine its selling price. What is the selling price of the book?

Answer:
$23
Step-by-step explanation:
15% is equivalent to 10% + 5%. 10% of $20= $2. 5% of 20=$1. 1+2=3. $20 + $3 = $23