If $\begin{bmatrix} x + y \ x - y \end{bmatrix} = \begin{bmatrix} 8 \ 4 \end{bmatrix}$, then the value of xy is:

1. 4

2. 8

3. 10

4. 12

If $\begin{bmatrix} p - q & 2q \ 2q + r & p + q \end{bmatrix} = \begin{bmatrix} 1 & 4 \ 9 & 5 \end{bmatrix}$, then the value of (p + q + r) is:

1. 8

2. 10

3. -5

4. -10

$\begin{bmatrix} 2 & 4 & 1 & 4 & 2 \ -1 & -2 & 3 & 5 & 1 \ 3 & 1 & 2 & 3 & 6 \end{bmatrix}$ is a matrix of the order:

1. 3 × 4

2. 5 × 3

3. 3 × 5

4. none of these

If matrix A of order 2 × 1 and matrix B of order 2 × 2 are added, then the order of the matrix A + B is:

1. 2 × 2

2. 2 × 1

3. 1 × 2

4. A + B is not possible