[tex]\blue\star[/tex] v = 20m\s
[tex]\blue\star[/tex] a = 3m\s^2
[tex]\blue\star[/tex] t = 4sec
Firstly we have to find u
[tex]\star[/tex] a = [tex]\dfrac{v - u}{t}[/tex]
[tex]\star[/tex] 3m\s =[tex]\dfrac{20 - u}{4}[/tex]
[tex]\star[/tex]12m\s = 20 - u
[tex]\star[/tex]20 - u = 12m\s
[tex]\star[/tex]- u = -8
[tex]\star[/tex] u = 8
Now we can easily find distance by using second equation of motion
[tex]\red\star[/tex]s = ut + 1\2 at^2
[tex]\red\star[/tex]s = 8(4) + 1\2(3)(16)
[tex]\red\star[/tex]s = 32 + 24
[tex]\red\star[/tex]s = 56
So distance is 56 m\s hope it helps