If $\begin{bmatrix} 2 & 3 \ -4 & 1 \end{bmatrix} + 2A = 4 \begin{bmatrix} -1 & 2 \ 3 & 4 \end{bmatrix}$, then the matrix A is:

1. $\begin{bmatrix} -3 & 5 \ 8 & 15 \end{bmatrix}$

2. $\begin{bmatrix} 5 & -3 \ 15 & 8 \end{bmatrix}$

3. $\begin{bmatrix} -3 & \dfrac{5}{2} \ 8 & \dfrac{15}{2} \end{bmatrix}$

4. $\begin{bmatrix} \dfrac{5}{2} & -3 \ \dfrac{15}{2} & 8 \end{bmatrix}$

The product AB of two matrices A and B is possible if:

1. A and B have the same number of rows.

2. The number of columns of A is equal to the number of rows of B.

3. The number of rows of A is equal to the number of columns of B.

4. A and B have the same number of columns.

If P and Q are two different matrices of order 3 × n and n × p, then the order of the matrix PQ is:

1. 3 × p

2. p × 3

3. n × n

4. 3 × 3

If $\begin{bmatrix} 2 & 4 \ 3 & 2 \end{bmatrix} \times P = \begin{bmatrix} 6 \ 8 \end{bmatrix}$, then the order of matrix P is:

1. 2 × 2

2. 2 × 1

3. 1 × 2

4. cannot be determined