Using rotational kinematic formulas

A fan initially rotates clockwise at $9{,}0 \,\dfrac{\text {rad}}{\text s}$9, comma, 0, start fraction, start text, r, a, d, end text, divided by, start text, s, end text, end fraction, but has a counterclockwise angular acceleration of $3{,}0\,\dfrac{\text {rad}}{\text s^2}$3, comma, 0, start fraction, start text, r, a, d, end text, divided by, start text, s, end text, squared, end fraction and reaches a counterclockwise angular speed of $27\,\dfrac{\text {rad}}{\text s}$27, start fraction, start text, r, a, d, end text, divided by, start text, s, end text, end fraction.

How much time did this change in the angular velocity take?

$\text s$start text, s, end text