As shown in the figure, two blocks, each with a mass of 3.2 kg ,...

Given:
Mass of each block, $m = 3.2 \text{ kg}$
Linear mass density of wire $AB$, $\mu_{AB} = 10 \text{ g m}^{-1} = 0.01 \text{ kg m}^{-1}$
Linear mass density of wire $CD$, $\mu_{CD} = 8 \text{ g m}^{-1} = 0.008 \text{ kg m}^{-1}$
Acceleration due to gravity, $g = 9.8 \text{ m s}^{-2}$

The tension in wire $CD$ is provided by the weight of the lower block:
$T_{CD} = mg = 3.2 \times 9.8 = 31.36 \text{ N}$

The speed of the transverse wave pulse in $CD$ is:
$v_{CD} = \sqrt{\dfrac{T_{CD}}{\mu_{CD}}} = \sqrt{\dfrac{31.36}{0.008}} = \sqrt{3920} \approx 62.6 \text{ m s}^{-1} \approx 63 \text{ m s}^{-1}$

The tension in wire $AB$ is provided by the weight of both blocks (neglecting the mass of the wires):
$T_{AB} = 2mg = 2 \times 3.2 \times 9.8 = 62.72 \text{ N}$

The speed of the transverse wave pulse in $AB$ is:
$v_{AB} = \sqrt{\dfrac{T_{AB}}{\mu_{AB}}} = \sqrt{\dfrac{62.72}{0.01}} = \sqrt{6272} \approx 79.2 \text{ m s}^{-1} \approx 79 \text{ m s}^{-1}$

Thus, the speeds in $AB$ and $CD$ are $79 \text{ m s}^{-1}$ and $63 \text{ m s}^{-1}$ respectively.