Pls answer 25th ques I didn't get this

Dear Student
In image attached by you it is not mentioned which is Q25. So I am solving the first question given in image.
$$\begin{gathered} {\mu }_r = 1.3 \\ {\epsilon }_r = 2.14 \\ Speed of electromagnetic waves is \\ v = \frac{1}{\sqrt{{\epsilon }_r{\epsilon }_o{\mu }_r{\mu }_o}} \\ as c =\frac{1}{\sqrt{{\epsilon }_o{\mu }_o}} \\ hence v =\frac{c}{\sqrt{{\epsilon }_r{\mu }_r}} \\ \therefore v = \frac{(3 \times {10}^8) }{\sqrt{(1.3 \times 2.14}} = 1.79 \times {10}^{8}m/s \end{gathered}$$

Regards