Let A be a 3 × 3 matrix with det ( A )=4. Let R_i denote the i^th row of A. If a matrix B is obtained by performing the operation R_2 → 2 R_2+5 R_3…

Let A be a $\displaystyle 3$ × $\displaystyle 3$ matrix with $\displaystyle \operatorname{det}(\mathrm{A})=4$. Let $\displaystyle \mathrm{R}_i$ denote the $\displaystyle i^{\text {th }}$ row of A. If a matrix B is obtained by performing the operation $\displaystyle R_2 \rightarrow 2 R_2+5 R_3$ on $\displaystyle 2 A$, then $\displaystyle \operatorname{det}(B)$ is equal to :