$(i)$ Isolate the point $P$

$(iii)$ The forces acting on it are$:$

Unknown tension $\mathrm{T}_{2}$ in cord $2$

Unknown tension $\mathrm{T}_{1}$ in cord $1$

 Known tension of $30 \mathrm{N}$ in the horizontal cord.

$(iii)$ $\mathrm{T}_{2}$ is resolved along $\mathrm{x}$ and $\mathrm{y}$ axes.

$(iv)$ Condition of equilibrium$:$

$\Sigma F_{x}=0 \Rightarrow 30-T_{2} \sin 45^{\circ}=0$               $…(1)$

and $\Sigma \mathrm{F}_{\mathrm{y}}=0 \Rightarrow \mathrm{T}_{2} \cos 45^{\circ}-\mathrm{T}_{1}=0$            $…(2)$

For body $B$ since the body $B$ is also in equilibrium,

Hence $\mathrm{T}_{1}=\mathrm{W}$            $…(3)$

$(v)$ After solving these equations,

we get $\mathrm{W}=30 \mathrm{N}$