We have that the formula for the distance is:
[tex]d=v_1t+\frac{1}{2}at^2[/tex]Given the information in the problem, we have the following:
[tex]\begin{gathered} v_1=14\frac{m}{s} \\ a=2\frac{m}{s^2}^{} \\ t=3s \end{gathered}[/tex]then, applying the formula we get the following:
[tex]\begin{gathered} d=(14\frac{m}{s})(3s)+\frac{1}{2}(2\frac{m}{s^2})(3s)^2 \\ =42m+\frac{18}{2}m=42m+9m=51m| \\ d=51m \end{gathered}[/tex]therefore, your friend traveled 51m