$\frac{\left(\Delta T _{ B }\right)_{ x }}{\left(\Delta T _{ B }\right)_{ y }}= m =\frac{\left( K _{ B }\right)_{ x } \times \text { molality }}{\left( K _{ B }\right)_{ y } \times \text { molality }}$
$=\frac{( T \cdot B )_{ x }^2}{( T \cdot B )_{ y }^2} \times \frac{\Delta H _{ y }}{\left(\Delta H _{ x }\right.}=(2)^2 \times 2=8$