Initial velocity=u=3m/s
Final velocity=v=10m/s
Time=t=8s
[tex]\boxed{\sf Acceleration=\dfrac{v-u}{t}}[/tex]
[tex]\\ \sf\longmapsto Acceleration=\dfrac{10-3}{8}[/tex]
[tex]\\ \sf\longmapsto Acceleration=\dfrac{7}{8}[/tex]
[tex]\\ \sf\longmapsto Acceleration=0.8m/s^2[/tex]
Using second equation of motion
[tex]\\ \sf\longmapsto s=ut+\dfrac{1}{2}at^2[/tex]
[tex]\\ \sf\longmapsto s=3(8)+\dfrac{1}{2}(0.8)(8)^2[/tex]
[tex]\\ \sf\longmapsto s=24+0.4(64)[/tex]
[tex]\\ \sf\longmapsto s=24+25.6[/tex]
[tex]\\ \sf\longmapsto s=49.6m[/tex]