Over a $14$-day period, data were collected on the number of passengers travelling on two ferries, $A$ and $Z.$ The results are presented to the right.

$\begin{array}{llllllllll}& & & & \mathrm{A}& & \mathrm{Z}& & & \\ & & 8& 7& 6& 2& & & & \\ & 7& 6& 4& 0& 3& 0& 5& 8& \\ & 8& 6& 5& 3& 4& 3& 4& 5& \begin{array}{ccc}7& 7& 7\end{array}\\ & & 5& 3& 3& 5& 0& 2& 6& \begin{array}{ccc}6& 9& \end{array}\\ & & & & & & & & & \\ & & & & & & & & & \end{array}$

Key$:3\left|5\right|0$
Represents $53$ passengers on $A$ and $50$ passengers on $Z$
The cost of a trip on ferry $A$ is $\$12.50$ and the cost of a trip on ferry $Z$ is $\$x.$ The takings on ferry $Z$ were $\$3.30$ less than the takings on ferry A over this period. Find the value of $x.$

Over a $14$-day period, data were collected on the number of passengers travelling on two ferries, $A$ and $Z.$ 

$\begin{array}{llllllllll}& & & & \mathrm{A}& & \mathrm{Z}& & & \\ & & 8& 7& 6& 2& & & & \\ & 7& 6& 4& 0& 3& 0& 5& 8& \\ & 8& 6& 5& 3& 4& 3& 4& 5& \begin{array}{ccc}7& 7& 7\end{array}\\ & & 5& 3& 3& 5& 0& 2& 6& \begin{array}{ccc}6& 9& \end{array}\\ & & & & & & & & & \\ & & & & & & & & & \end{array}$

Key$:3\left|5\right|0$
Represents $53$ passengers on $A$ and $50$ passengers on $Z$

Find the least and greatest possible number of days on which the two ferries could have carried exactly the same number of passengers.

The total numbers of eggs laid in the nests of two species of bird were recorded over several breeding seasons.
The numbers of eggs laid in the nests of $10$ wrens and $10$ dunnocks are:
Wrens: $22, 18, 21, 23, 17, 23, 20, 19, 24, 13.$
Dunnocks: $28, 24, 23, 19, 30, 27, 22, 25, 22, 17.$
Represent the data in a back-to-back stem-and-leaf diagram with rows of width $5.$

Given that all of these eggs hatched and that the survival rate for dunnock chicks is $92\%,$ estimate the number of dunnock chicks that survived.

The total numbers of eggs laid in the nests of two species of bird were recorded over several breeding seasons.
The numbers of eggs laid in the nests of $10$ wrens and $10$ dunnocks are:
Wrens: $22, 18, 21, 23, 17, 23, 20, 19, 24, 13.$
Dunnocks: $28, 24, 23, 19, 30, 27, 22, 25, 22, 17.$
Represent the data in a back-to-back stem-and-leaf diagram with rows of width $5.$

Find the survival rate for the wren chicks, given that $14$ did not survive.

This back-to-back stem-and-leaf diagram shows the percentage scores of the $25$ students who were the top performers in an examination.
 

$\begin{array}{cll}\text{ Girls (12) }& & \text{ Boys (13) }\\ \begin{array}{cccccc}& & & & 4& 1\\ & & & 8& 6& 6\\ & & 3& 2& 1& 0\\ & & & 8& 7& 7\\ & & & & & \end{array}& \begin{array}{c}8\\ 8\\ 9\\ 9\\ \end{array}& \begin{array}{cccccc}2& & & & & \\ 5& 9& & & & \\ 0& 1& 3& 3& 4& 4\\ 5& 6& 6& 9& & \\ & & & & & \end{array}\end{array}$

Key $:1\mathbf{\left|}8\mathbf{\right|}2$ represents $81\%$ for a girl and $82\%$ for a boy
The $25$ students are arranged in a line in the order of their scores. Describe the student in the middle of the line and find the greatest possible number of boys in the line who are not standing next to a girl.