Lorentz Force

2021 1 question

1. In the product $\vec{F}=q(\vec{v}\times\vec{B})=q\vec{v}\times(B\hat{i}+B\hat{j}+B_0\hat{k})$. For $q=1$ and $\vec{v}=2\hat{i}+4\hat{j}+6\hat{k}$ and $\vec{F}=4\hat{i}-20\hat{j}+12\hat{k}$. What will be the complete expression for $\vec{B}$?