let r be the radius of the smallest sphere
let r be the radius of the largest sphere
where :
R=1.5r
by ratio an proportion of similar objects
[tex] \frac{ r^{3} }{ R^{3} } = \frac{V_s}{V_r} [/tex]
[tex] \frac{ r^{3} }{(1.5r)^{3} } = \frac{V_s}{V_l} [/tex]
[tex]V_l=3.375V_s[/tex]
so the Volume of the largest sphere is 3.375 times bigger than the smallest sphere.