\[ \bar{x}=\frac{\Sigma x}{n} \]

\[ \Sigma x = 28+16+83+72+105+55+6+35=400,\quad n=8 \]

\[ \bar{x}=\frac{400}{8}=50. \]

\[ \Sigma x = 7.3+8.6+11.7+9.1+1.7+4.2 = 42.6,\quad n=6 \]

\[ \bar{x}=\frac{42.6}{6}=7.1. \]

Convert to improper fractions / decimals and sum.

\[ \Sigma x = 3.5+5.25+9.75-4.25+7.375 = 21.625 \]

\[ \bar{x}=\frac{21.625}{5} =4.325 =4\frac{13}{40}. \]

\[ \frac{(15+31+47+83+97+119)+p^2}{7}=63 \]

\[ \frac{392+p^2}{7}=63 \;\Rightarrow\; p^2=49 \]

\[ p=\pm 7. \]

\[ \frac{6+29+3+14+q+(q+8)+q^2+(10-q)}{8}=20 \]

\[ \frac{q^2+q+70}{8}=20 \;\Rightarrow\; q^2+q-90=0 \]

\[ (q-9)(q+10)=0 \;\Rightarrow\; q=9 \text{ or } q=-10. \]

\[ \bar{x}=\frac{\Sigma x}{n}=\frac{325.5}{14}=23.25. \]

\[ \Sigma y = n\,\bar{y}=45\times 23.6=1062. \]

\[ n=\frac{\Sigma z}{\bar{z}}=\frac{4598}{52.25}=88. \]

\[ \bar{x}=\frac{\Sigma xf}{\Sigma f} \;\Rightarrow\; \Sigma f=\frac{\Sigma xf}{\bar{x}} =\frac{86}{\,7\frac16\,} =\frac{86}{43/6}=12. \]

\[ \Sigma xf = \bar{x}\,\Sigma f = 0.842\times 135 = 113.67. \]