Each question is followed by four options lettered A to D. Find the correct option for each question and shade in pencil on your answer sheet the answer space which bears the same letter as the option you have chosen. Give only one answer to each question.

$$
(6an + 2n) - (3a + 1)
$$

$$
2n(3a + 1) - 1(3a + 1)
$$

$$
(3a + 1)(2n - 1)
$$
The factored expression is $\boxed{\text{B. } (3a + 1)(2n - 1)}$.

$$
17 - 9 < -2x
$$
$$
8 < -2x
$$

$$
3x + 102^\circ = 180^\circ
$$

$$
3x = 180^\circ - 102^\circ
$$
$$
3x = 78^\circ
$$

$$
x = \frac{78^\circ}{3}
$$
$$
x = 26^\circ
$$
The value of x is $\boxed{\text{C. } x = 26^\circ}$.

$$
2x + 126^\circ + x = 180^\circ
$$

$$
3x + 126^\circ = 180^\circ
$$

$$
3x = 180^\circ - 126^\circ
$$
$$
3x = 54^\circ
$$

$$
x = \frac{54^\circ}{3}
$$
$$
x = 18^\circ
$$
The value of x is $\boxed{\text{D. } x = 18^\circ}$.

$$
C = 2 \times \frac{22}{7} \times 28\,m
$$

$$
C = 2 \times 22 \times \frac{28}{7}\,m
$$
$$
C = 2 \times 22 \times 4\,m
$$
$$
C = 44 \times 4\,m
$$
$$
C = 176\,m
$$
The distance covered is $\boxed{\text{C. } 176m}$.

$$
\text{Total time} = 2 \text{ hours} \times 60 \text{ minutes/hour} = 120 \text{ minutes}
$$

$$
\text{Remaining time} = 120 \text{ minutes} - 20 \text{ minutes} = 100 \text{ minutes}
$$

$$
\text{Remaining questions} = 9 - 1 = 8 \text{ questions}
$$

$$
\text{Time per remaining question} = \frac{100 \text{ minutes}}{8 \text{ questions}} = 12.5 \text{ minutes/question}
$$
He spent $\boxed{\text{D. } 12.5 \text{ minutes}}$ on each of the other questions.

$$
V_{\text{total}} = \text{length} \times \text{width} \times \text{height}
$$
$$
V_{\text{total}} = 5\,m \times 3\,m \times 4\,m
$$
$$
V_{\text{total}} = 60\,m^3
$$

$$
V_{\text{water}} = \frac{2}{3} \times V_{\text{total}}
$$
$$
V_{\text{water}} = \frac{2}{3} \times 60\,m^3
$$
$$
V_{\text{water}} = 2 \times \frac{60}{3}\,m^3
$$
$$
V_{\text{water}} = 2 \times 20\,m^3
$$
$$
V_{\text{water}} = 40\,m^3
$$
The volume occupied by the water is $\boxed{\text{B. } 40m^3}$.

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

$$
2a - b = \begin{pmatrix} 2 \\ -4 \end{pmatrix} - \begin{pmatrix} -5 \\ -3 \end{pmatrix}
$$
$$
2a - b = \begin{pmatrix} 2 - (-5) \\ -4 - (-3) \end{pmatrix}
$$
$$
2a - b = \begin{pmatrix} 2 + 5 \\ -4 + 3 \end{pmatrix}
$$
$$
2a - b = \begin{pmatrix} 7 \\ -1 \end{pmatrix}
$$
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 option is GH¢471.00, but my calculation is 470. Assuming there might be a typo in the options or my interpretation of the numbers. If the option is exactly 471, it's slightly off. However, 470 is the closest and correct calculation.)

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

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

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

$$
x = \frac{0}{2}
$$
$$
x = 0
$$
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 $\boxed{\text{C. } \frac{5}{9}}$.