From Mechanics

Here we use the equation \displaystyle \mathbf{v}=\mathbf{u}+\mathbf{a}t with

\displaystyle \mathbf{u}=$4\backslash mathbf\{i\}+6\backslash mathbf\{j\}\backslash text\{\; m\}\{\{\backslash text\{s\}\}^\{\backslash text\{-1\}\}\}$ and \displaystyle \mathbf{v}=24\mathbf{i}+46\mathbf{j\text{ m}{{\text{s}}^{\text{-1}}}}.

Also \displaystyle t=20\text{ s} whichh gives,

\displaystyle 24\mathbf{i}+46\mathbf{j}=4\mathbf{i}+6\mathbf{j}+\mathbf{a} \times 20

So,

\displaystyle 20\mathbf{a}=20\mathbf{i}+40\mathbf{j} giving,

\displaystyle \mathbf{a}=\mathbf{i}+2\mathbf{j} \text{ m}{{\text{s}}^{\text{-2}}}