Suppose a revenue function is given by:

$\displaystyle {R}{\left({q}\right)}=-{q}^{{3}}+{107}{q}$
where $\displaystyle {q}$ is thousands of units and $\displaystyle {R}{\left({q}\right)}$ is thousands of dollars.

For what value of $\displaystyle {q}$ is revenue maximized. Round your answer to the nearest tenth (one decimal place).

$\displaystyle {q}=$ thousand units