Final answer:
To find 65% of a number, you can multiply the number by 0.65.
Step-by-step explanation:
To find the number 65% of a certain number, you can use the equation: 0.65 * x = 13, where x represents the unknown number. To solve for x, divide both sides of the equation by 0.65. This gives you x = 13 / 0.65, which simplifies to x = 20. So, the number is 20.