Sixteen bank accounts have been accidentally under-credited by the following amounts, denoted by $\$x.$

$\begin{array}{llllllll}917.95& 917.98& 918.03& 917.97& 918.01& 917.94& 918.05& 918.07\\ 918.02& 917.93& 918.01& 917.88& 918.10& 917.85& 918.11& 917.94\end{array}$

To calculate $\overline{x}$ manually, Fidel and Ramon code these figures using $\left(x-917\right)$ and $\left(x-920\right),$ respectively.

Who has the simpler maths to do? Explain your answer.

All the interior angles of $n$ triangular metal plates, denoted by $y°,$ are measured. State the number of angles measured and write down the value of $\overline{y}.$

All the interior angles of $n$ triangular metal plates, denoted by $y°,$ are measured. Hence, or otherwise, find the value of $\Sigma \left(y-30\right).$

Students investigated the prices in dollars $\left(\$\right)$ of $1$ litre bottles of a certain drink at $24$ shops in a town and at $16$ shops in surrounding villages. Denoting the town prices by $t$ and the village prices by $v,$ the students' data are summarised by the totals $\Sigma \left(t-1.1\right)=1.44$ and $\Sigma \left(v-1.2\right)=0.56.$

Find the mean price of $1$ litre of this drink at all the shops at which the students collected their data.

The masses, $x \mathrm{kg},$ of $12$ objects are such that $\overline{x}=0.475.$ Find the value of $\Sigma 1000x$ and state what it represents.

carats, given that $1$ carat is equivalent to $200$ milligrams

The total mass of gold extracted from a mine is denoted by $\Sigma x,$ which is measured in grams. Find an expression in $x$ for the total mass in:

carats, given that $1$ carat is equivalent to $200$ milligrams

The total mass of gold extracted from a mine is denoted by $\Sigma x,$ which is measured in grams. Find an expression in $x$ for the total mass in:

kilograms.