Recall that average velocity is given by
[tex]v_{\rm ave}=\dfrac{\Delta x}{\Delta t}[/tex]
Under constant acceleration, we also have
[tex]v_{\rm ave}=\dfrac{v_i+v_f}2[/tex]
Then
[tex]\dfrac{\Delta x}{\Delta t}=\dfrac{v_i+v_f}2[/tex]
[tex]\implies\dfrac{110\,\mathrm m}{\Delta t}=\dfrac{22\frac{\rm m}{\rm s}+3.0\frac{\rm m}{\rm s}}2[/tex]
[tex]\implies\boxed{\Delta t=8.8\,\mathrm s}[/tex]
