Matrices Practice Questions Ques14
Question: If $A = \begin{pmatrix} 1 & 2 \\ 3 & 4 \end{pmatrix}$ and $B = \begin{pmatrix} 2 & 0 \\ 1 & 3 \end{pmatrix}$, what is $AB$?
Options:
(A) $\begin{pmatrix} 4 & 6 \\ 10 & 15 \end{pmatrix}$
(B) $\begin{pmatrix} 4 & 6 \\ 10 & 12 \end{pmatrix}$
(C) $\begin{pmatrix} 4 & 6 \\ 9 & 15 \end{pmatrix}$
(D) $\begin{pmatrix} 4 & 6 \\ 10 & 18 \end{pmatrix}$
Show Answer
Answer: B
Explanation:
(A) Incorrect. This is not the correct result of the matrix multiplication.
(B) Correct. Matrix multiplication is performed as follows: $\begin{pmatrix} 1 \cdot 2 + 2 \cdot 1 & 1 \cdot 0 + 2 \cdot 3 \\ 3 \cdot 2 + 4 \cdot 1 & 3 \cdot 0 + 4 \cdot 3 \end{pmatrix} = \begin{pmatrix} 4 & 6 \\ 10 & 12 \end{pmatrix}$.
(C) Incorrect. This is not the correct result of the matrix multiplication.
(D) Incorrect. This is not the correct result of the matrix multiplication.
BETA
