Answer
The number is $31$.
Work Step by Step
Let $x$ be the unknown number.
Then twice the number is $2x$.
Thus, the equation needed to find the unknown number is:
$$2x+13=75$$
Solve the equation:
$$\begin{align*}
2x+13-13&=75-13 &\text{Subtract 13 from each side.}\\
2x&=62 &\text{Simplify.}\\
\frac{2x}{2}&=\frac{62}{2} &\text{Divide 2 to both sides.}\\
x&=31 &\text{Simplify.}
\end{align*}$$
