The excess of pressure inside a soap bubble is twice the excess pressure inside a second soap bubble. The volume of the first bubble is n times the volume of the second where n  is______

The excess pressure in soap bubble $p=\frac{4T}{r}$ 
Where T=  Surface Tension
r= radius of soap bubble
$\frac{4T}{r_1}=2\times \frac{4T}{r_2}$ 
or   $r_2=2r_1$
Given the volume of the first bubble is n times the volume of the second
 $V_1=n{V}_2$
$\frac{4}{3}\pi r_1^3=n\times \frac{4}{3}\pi r_2^3=n\times \frac{4}{3}\pi {\left(2r_1\right)}^3$  
 $\Rightarrow n=0.125$