Q45 / 160 · WBJEE 2010 · Mathematics
If the matrices $A=\left[\begin{array}{lll}2 & 1 & 3 \\ 4 & 1 & 0\end{array}\right]$ and $B=\left[\begin{array}{rr}1 & -1 \\ 0 & 2 \\ 5 & 0\end{array}\right]$, then $\mathrm{AB}$ will be
- Correct answerA$\left[\begin{array}{cr}17 & 0 \\ 4 & -2\end{array}\right]$
- B$\left[\begin{array}{ll}4 & 0 \\ 0 & 4\end{array}\right]$
- C$\left[\begin{array}{cr}17 & 4 \\ 0 & -2\end{array}\right]$
- D$\left[\begin{array}{ll}0 & 0 \\ 0 & 0\end{array}\right]$
Solution
$$
\text { Hints : } \mathrm{AB}=\left[\begin{array}{lll}
2 & 1 & 3 \\
4 & 1 & 0
\end{array}\right]\left[\begin{array}{rr}
1 & -1 \\
0 & 2 \\
5 & 0
\end{array}\right]=\left[\begin{array}{lr}
17 & 0 \\
4 & -2
\end{array}\right]
$$
Hence, the correct answer is option: 'A'.