Answer
$-7.5cm$
Work Step by Step
First we can use the given values from the table in equation (34-10) to find the focal point.
$\frac{1}{f}=(n-1)(\frac{1}{r_1} - \frac{1}{r_2})$
Solving for $f$, we obtain:
$f=((n-1)(\frac{1}{r_1} - \frac{1}{r_2}))^{-1}$
$f=((1.50-1)(\frac{1}{-30cm} - \frac{1}{30cm}))^{-1}$
$f=-30cm$
Now we can use equation (34-9) to find the image distance, $i$.
$\frac{1}{p}+\frac{1}{i}=\frac{1}{f}$
Solving for $i$, we have:
$i=(\frac{1}{f}-\frac{1}{p})^{-1}$
$i=(\frac{1}{-30cm}-\frac{1}{10cm})^{-1}$
$i=-7.5cm$