If a = [(-2), (5)] and b = [(-5), (-3)] find 2a - b

$$
2a = 2 \begin{pmatrix} 1 \\ -2 \end{pmatrix} = \begin{pmatrix} 2 \times 1 \\ 2 \times -2 \end{pmatrix} = \begin{pmatrix} 2 \\ -4 \end{pmatrix}
$$

$$
2a - b = \begin{pmatrix} 2 \\ -4 \end{pmatrix} - \begin{pmatrix} -5 \\ -3 \end{pmatrix}
$$
$$
2a - b = \begin{pmatrix} 2 - (-5) \\ -4 - (-3) \end{pmatrix}
$$
$$
2a - b = \begin{pmatrix} 2 + 5 \\ -4 + 3 \end{pmatrix}
$$
$$
2a - b = \begin{pmatrix} 7 \\ -1 \end{pmatrix}
$$
The result is $\boxed{\text{D. } \begin{pmatrix} 7 \\ -1 \end{pmatrix}}$.

$$
\frac{S + M}{2} = 53
$$
$$
S + M = 53 \times 2 = 106
$$

$$
E = 50
$$
$$
SS = 60
$$

$$
\text{Total Score} = (S + M) + E + SS
$$
$$
\text{Total Score} = 106 + 50 + 60 = 216
$$

$$
\text{Mean Score} = \frac{\text{Total Score}}{\text{Number of Subjects}}
$$
$$
\text{Mean Score} = \frac{216}{4}
$$
$$
\text{Mean Score} = 54
$$
Her mean score in all four subjects is $\boxed{\text{D. } 54}$.

$$
\text{Probability} = 28\%
$$

$$
\text{Probability} = \frac{28}{100}
$$

$$
\text{Probability} = \frac{28 \div 4}{100 \div 4} = \frac{7}{25}
$$
The probability is $\boxed{\text{A. } \frac{7}{25}}$.

$$
15 \text{ notes} \times 20 \text{ cedis/note} = 300 \text{ cedis}
$$

$$
14 \text{ notes} \times 10 \text{ cedis/note} = 140 \text{ cedis}
$$

$$
15 \text{ notes} \times 2 \text{ cedis/note} = 30 \text{ cedis}
$$

$$
\text{Total Sales} = 300 \text{ cedis} + 140 \text{ cedis} + 30 \text{ cedis}
$$
$$
\text{Total Sales} = 470 \text{ cedis}
$$
Her total sales are $\boxed{\text{C. GH}\text{¢}471.00}$. (Note: The calculated value is GH¢470.00, but the closest option is GH¢471.00. Assuming there might be a slight discrepancy in the options or the question's intended values.)

$$
4x - 2x - 10 = -10
$$

$$
(4x - 2x) - 10 = -10
$$
$$
2x - 10 = -10
$$

$$
2x = -10 + 10
$$
$$
2x = 0
$$

$$
x = \frac{0}{2}
$$
$$
x = 0
$$
The solution is $\boxed{\text{B. } x = 0}$.

$$
\text{Total balls} = \text{Number of green balls} + \text{Number of white balls}
$$
$$
\text{Total balls} = 10 + 8 = 18
$$

$$
\text{Green balls} = 10
$$

$$
P(\text{Green}) = \frac{\text{Number of green balls}}{\text{Total number of balls}}
$$
$$
P(\text{Green}) = \frac{10}{18}
$$

$$
P(\text{Green}) = \frac{10 \div 2}{18 \div 2} = \frac{5}{9}
$$
The probability that the ball is green is $\boxed{\text{C. } \frac{5}{9}}$.