If the vectors $p\hat i+\hat j+\hat k, \hat i+q\hat j+\hat k$ and $\hat i+\hat j+r\hat k (p≠q≠r≠1)$ are coplanar, then the value of $pqr-(p+q+r)$, is
Answer & explanation
Correct answer: option 3
If given vectors are coplanar, then
$\begin{vmatrix}p&1&1\\1&q&1\\1&1&r\end{vmatrix}=0⇒ pqr-(p+q+r)=-2$