The speed of the smaller stone is given as two times the speed of the larger stone.
Let v be the initial velocity of the larger stone.
Then the initial velocity of the smaller stone is,
[tex]v^{\prime}=2v[/tex]As the given kinematic equation is,
[tex]x=\frac{v^2}{2g}[/tex]Where x is the distance travelled in the upward direction and g is the acceleration due to gravity.
For the smaller stone, the distance travelled is,
[tex]\begin{gathered} x=\frac{v^{\prime2}}{2g} \\ x=\frac{(2v)^2}{2g} \\ x=4\times\frac{v^2}{2g} \\ x=4\times\text{distance travelled by the larger stone} \end{gathered}[/tex]Thus, the distance travelled by the small stone in the upward direction is 4 times the distance travelled by the larger stone.