Let a = i - j +2 k and let b be a vector such that a × b =2 i - k and a · b =3. Then the projection of b on the vector a - b is:

Let $\displaystyle \vec{a}=\hat{i}-\hat{j}+2 \hat{k}$ and let $\displaystyle \vec{b}$ be a vector such that $\displaystyle \vec{a} \times \vec{b}=2 \hat{i}-\hat{k}$ and $\displaystyle \vec{a} \cdot \vec{b}=3$. Then the projection of $\displaystyle \vec{b}$ on the vector $\displaystyle \vec{a}-\vec{b}$ is: