Answer
Range =$29$
Sample variance = $s^{2}=75.71$
Sample standard deviation = $s = 8.7$
Work Step by Step
Recall the shortcut formula for calculating the variance ($s^{2}$)$:$
$$s^{2}=\frac{\sum x_{i}^{2}-\frac{(\sum x_{i})^{2}}{n}}{n-1}$$
Create a table of the number of books read by students marked with an $A$, with which we compute $\displaystyle \sum x_{i}$ and $\displaystyle \sum x_{i}^{2}$:
$$ \begin{array}{rrr}
x & \rm Grade & x^{2}\\
\hline 53 & \mathrm{A} & 2809\\
42 & \mathrm{A} & 1764\\
40 & \mathrm{A} & 1600\\
39 & \mathrm{A} & 1521\\
34 & \mathrm{A} & 1156\\
34 & \mathrm{A} & 1156\\
30 & \mathrm{A} & 900\\
24 & \mathrm{A} & 576\\
\hline\rm Sum=296 & & 11482
\end{array}$$
Plug in the given values (there are $n=8$ data items):
$$\begin{align*}
s^{2}&= \displaystyle \frac{11482-\frac{(296)^{2}}{8}}{8-1} & & \\
& =75.71\\\\
s&= \sqrt{75.71} =8.7 \end{align*}$$
The range is the difference between the largest and smallest data item:
$$53-24=29$$
