How do you define a variable and write an algebraic expression for the phrase: 10 plus the quotient of a number and 15?

$10 + x \div 15$
$10 + \frac{x}{15}$
Plus $10$ means to add $10$. The quotient of a number and $15$ means that the number is divided by $15$. Let $x$ represent the number. The quotient of the number and $15$ can be written as $x \div 15$ or $\frac{x}{15}$.