
let spring constant of spring in figure $A$ is $K.$ now spring constant of each spring in figure $B$ is $3 \mathrm{K}$
in figure, all springs are in parallel so $(K_{eq } ) _ { B }$ $=9 \mathrm{K}$
time period $\mathrm{T}=2 \pi \sqrt{\frac{\mathrm{M}}{\mathrm{K}}}$
$\frac{\mathrm{T}_{\mathrm{A}}}{\mathrm{T}_{\mathrm{B}}}=\sqrt{\frac{\mathrm{K}_{\mathrm{B}}}{\mathrm{K}_{\mathrm{A}}}}=3$

